Danilo Billi was from Livorno.

The 8^o Gruppo was transferred to Libya in September 1935 and in 1940, it was the oldest colonial fighter unit of the Regia Aeronautica and was equipped with Fiat CR.32quater (a tropical version of the classic Fiat design with enlarged oil cooler and other slight improvements that enhanced its low altitude performances).
The 8^o Gruppo (92^a, 93^a and 94^a Squadriglie) was commanded by Maggiore Vincenzo La Carruba and started the war based at Tobruk T2 airfield with a full complement of 25 Fiat CR.32quaters.
Pilots in the 94^a Squadriglia on 11 June were: Capitano Franco Lavelli (CO), Tenente Giovanni Tadini, Sottotenente Giacomo Maggi, Sottotenente Nunzio De Fraia, Sergente Maggiore Trento Cecchi, Sergente Maggiore Billi, Sergente Maggiore Alessandro Ruzzene and Sergente Maggiore Arturo Cardano. These pilots had eight CR.32quaters available on 11 June.

On 11 June, the Regia Aeronautica was in alarm readiness from 00:00 and a standing patrol of three Fiat CR.32s of the 8^o Gruppo was maintained over the Tobruk T2 airfield and Tobruk harbour. This was not possible over El Adem T3 because there were no fighter units based here.
At 05:00, seven Fiats of the 93^a Squadriglia, 8^o Gruppo, scrambled to meet a formation of seven British bombers signalled by the observation post at Bardia, flying in eastward direction. The fighters climbed to 2000 metres and the British formation was seen as if it was coming back from an incursion over T3. The CR.32s started in pursuit but were unable to reach them and the bombers disappeared in the dawn mist.
Two hours later, at around 07:00, seven more CR.32s scrambled to meet another attack directed on El Adem. Six of the aircraft were from the 94^a Squadriglia (Capitano Franco Lavelli, Tenente Giovanni Tadini, Sergente Maggiore Alessandro Ruzzene, Sergente Maggiore Billi, Sergente Maggiore Arturo Cardano and Sergente Maggiore Trento Cecchi while the seventh was from the 92^a Squadriglia (CO Martino Zannier). The Italian pilots had a slight height advantage over the seven Blenheims and this made it possible to intercept. The Fiat pilots claimed two bombers shot down (one into the sea and one from which the crew was seen to bale out) and four damaged, all shared among the seven pilots. Zannier returned at 07:40 with the engine on his fighter damaged and having expended 500 rounds of ammunition. The pilots of the 94^a Squadriglia landed five minutes later, having spent 3770 rounds of ammunition.
At 11:20, Tenente Alberto Argenton of the 93^a Squadriglia together with Tenente Riccardo Marcovich of the 92^a Squadriglia, carried out a visual reconnaissance over the British airstrip of Tishididda. They landed at 12:50 reporting the absence of enemy planes.
At 15:00, a patrol of five CR.32s of the 93^a Squadriglia, led by Tenente Gioacchino Bissoli and including Tenente Alberto Argenton, Sergente Maggiore Italo Bertinelli, Sergente Maggiore Duilio Bernardi and Sergente Maggiore Luigi Di Lorenzo intercepted another formation of six bombers. With a swift attack Bissoli shot down a Blenheim that fell down close to T3 (nobody was seen to jump from the aircraft) while his wingmen claimed damage to two others before the bombers were able to escape. The Squadriglia diary reported that all the surviving enemy bombers were damaged with the use of 1050 rounds.
Totally the 25 Fiat CR.32s of the 8^o Gruppo made 96 sorties during the day.
The Italian fighters had clashed with Blenheims from 202 Group (45, 55, 113, and 211 Squadrons). A few minutes after midnight six Bristol Blenheim Mk.I crews of 211 Squadron were briefed to carry out an armed reconnaissance at dawn of targets in Libya. Their target was El Adem, photographing from Derna to Giarabub as they went. During a reconnaissance flight over the Giarabub-Capuzzo areas a Blenheim Mk.I of 211 Squadron piloted by Pilot Officer Eric Bevington-Smith was obliged to force-land with engine trouble. It is possible that the Blenheims from 211 Squadron were the ones the 8^o Gruppo in vain tried to intercept at 05:40.
These were followed by eight Bristol Blenheim Mk.Is of 45 Squadron that took off from Fuka at 04:15 and attacked the airfield of El Adem T3. Initially the raid was to be against Tobruk s harbour, but the reconnaissance of 211 Squadron showed it deprived of any significant target. The British formation was composed of Squadron Leader Dallamore (Blenheim Mk.I L8478), Flying Officer Williams (L8469), Sergeant Thurlow (L8519), Flight Lieutenant Troughton Smith (L8481), Pilot Officer Gibbs (L4923), Sergeant Bower (L8476), Flying Officer Rixson (L8524) and Flying Officer Finch (L8466). The British pilots returned from T3 claiming that they had attacked at 05:40 with 40lb, 20lb and 4lb incendiary bombs and also had strafed in subsequent passes with front and rear guns. Although no enemy aircraft were encountered, the ground defences had been in action immediately. These were described as not heavy and in fact it is known that at the beginning of the conflict for the defence of all the 35 air strips of Cirenaica, the Italians had only 17 ex-Austrian Schwarzlose 8mm gun of WW I vintage armed with standard ammunition and with a maximum range of 600 meters. Later more details enriched the description of this first attack, reporting that the returning crews had claimed that the entire manpower of the Italian base had been assembled on parade, as if the commanding officer had been reading a signal from Marshal Italo Balbo (Italian Commander-in-Chief) announcing the declaration of war. The Blenheims had hit two hangars burning them, then had strafed and bombed the Italian aircraft that were parked in rows as in peacetime and not dispersed destroying several of them. Three Blenheims failed to return and two more were damaged. Blenheim Mk.I L8476 was reportedly hit by light flak shortly after the last attack, caught fire and crashed into the sea killing the crew; Sergeant Peter Bower (RAF no. 524415), Sergeant Stanley George Fox (RAF no. 747815) and Aircraftman 1st Class John William Allison (RAF no. 543233). Blenheim Mk.I L8519 was damaged during the raid and crash-landed at Sidi Barrani where it burst into flames killing its crew; Sergeant Maurice Cresswell Thurlow (RAF no. 565808), Sergeant Bernard Alfred Feldman (RAF no. 747967) and Aircraftman 1st Class Henry Robinson (RAF no. 548048). Blenheim Mk.I L8466 suffered an engine failure over the target (possibly hit by Italian fire), the other engine failed after 100 miles during the return journey eastwards and the aircraft made a wheels-up forced landing near Buq-Buq. The crew (Flying Officer A. Finch, Sergeant R. Dodsworth and Leading Aircraftman Fisher) was rescued by the British Army while the aircraft was later recovered and repaired. It seems possible that these Blenheims were in fact claimed by the pilots of the 92^a and 94^a Squadriglie.
The first raid of the war brought also one of the first mysteries of the campaign, as it is not sure, from the comparison of the Italian and British documents, which were the opponents of the 8^o Gruppo during this early morning raid. It seems here right to explain that the time in Italy (and assumingly also in Libya) at the beginning of the war was Greenwich Mean Time (G.M.T.) +1h. On the other hand from available documents it transpires that in Egypt was still in use the solar time that was G.M.T. + 2h, (it seems that only after 15 July did also Egypt adopted daylight saving time, which is G.M.T +3h). Thus, even if exceptions to this rule has been noted in the documents consulted, it seems that on 11 June 1940 the time recorded British was one hour in advance of that recorded by the Italians. This is the strongest clue to assume that 45 Squadron was in fact the unit that the 8^o Gruppo failed to intercept during its first morning pursuit, because the RAF recorded this raid at 05:40, which was 04:40 in Italian time, quite close to the 05:00 of the first inconclusive scramble of the 93^a Squadriglia.
If we accept this, however, the opponents of the 8^o Gruppo, against which 4270 round of ammunition were expanded and which damaged Zannier s Fiat, remained undisclosed because no other British raids was reportedly performed in the morning. Additionally it is known that Balbo himself, commenting the day s actions credited all the three victories claimed by the Italians to the fighters and none to AA that was explicitly termed as non existent . As a point of interested, it is also worth noting that Italy adopted daylight saving time (G.M.T. +2h) on 15 June 1940 and kept it for the rest of the war. Thus, from 15 June until 15 July, Italians and British recorded the same time (G.M.T + 2h), then after that date the British time returned one hour in advance of the Italian one.
In the afternoon, 55 and 113 Squadrons were transferred from Ismailia to Fuka and nine planes from each Squadron were bombed up and attacked El Adem T3 once again starting from 14:15. A Flight from 55 Squadron included Blenheim Mk.Is L8530 (Flight Lieutenant Cox (acting Squadron Leader), Sergeant Wagstaff and Corporal Bennett), L8391 (Pilot Officer Walker, Sergeant Kavanagh and Leading Aircraftman Noble) and L8667 (Sergeant Day, Sergeant Browning and Leading Aircraftman McGarry). B Flight included Blenheim Mk.Is L1538 (Flight Lieutenant H. R. Goodman, Sergeant Wiles and Leading Aircraftman Jone), L4818 (Pilot Officer M. S. Ferguson, Pilot Officer H. A. W. How and Leading Aircraftman Cherry) and L8398 (Pilot Officer R. H. Nicolson, Leading Aircraftman Bartram and Leading Aircraftman Davison). C Flight included Blenheim Mk.Is L4820 (Flying Officer F. H. Fox, Sergeant Nicholas and Leading Aircraftman Klines), L6672 (Pilot Officer Godrich, Pilot Officer Redfern and Leading Aircraftman Thompson) and L8390 (Pilot Officer Smith, Sergeant Clarke and Leading Aircraftman Dews).
The returning pilots reported that the aircraft of the base were still not dispersed and claimed the damaging or destruction on ground of eighteen of them, together with additional damage on the hangars of the base. This time enemy aircraft were encountered and one Blenheim Mk.IV of 113 Squadron was admitted lost to them when L4823 was shot down (most probably by Tenente Bissoli) in flames 7 km east of El Adem. The crew of Flight Lieutenant D. Beauclair, Warrant Officer H. J. Owen and Sergeant J. Dobson were all badly burned, but walked for eight hours before being captured by an Italian Marine post east of Tobruk. Two Blenheims from 55 Squadron were badly damaged but were able to regain British territory. They had encountered some accurate AA fire and reported that although CR.32 fighters were seen they didn t engage. L1538 received five hits on the starboard engine cowling, the engine stopped through lack of petrol and the aircraft made an emergency landing at Mersa Matruh, while L8398 received a bullet in the undercarriage that collapsed on landing at Mersa Matruh. The two aircraft were left there. The starboard engine of L4820, which had been followed by two Fiat fighters that reportedly scored no hits on it, seized when over Mersa Matruh. The bomber was however able to successfully land at Fuka. In all 26 bombers attacked T3 during the day hitting it with 416 forty pounds bombs, 524 twenty pounds bombs and 2080 four pounds incendiary bombs.
The Italians reported three different raids against El Adem (made by a reported six-nine-six enemy bombers). The 44^o Gruppo lost one completely burnt out SM 79, two more lightly damaged (RS) and two more seriously damaged (they had to be repaired in the local S.R.A.M.). The Gruppo also suffered three dead and twenty-four wounded.
Three Ro.37s and two Ca.309s were also heavily damaged and two Ro.37s and six S.81s were lightly damaged. Ten more soldiers were wounded.

At 11:25 on 22 October, Sergente Maggiore Billi from the 94^a Squadriglia, 8^o Gruppo scrambled from Menastir to intercept a lone reconnaissance aircraft identified as a Wellington. He was soon followed by Tenente Vittorio Gnudi and Sergente Alberto Bottazzi (also from the 94^a Squadriglia). Sergente Maggiore Billi attacked immediately, starting a fire on the British aircraft. The three pilots were back between 12:20 and 12:45 and Billi was credited with the victory after having used 220 rounds of ammunition.
He had intercepted a reconnaissance Blenheim Mk.IV of 113 Squadron (T2063) piloted by Sergeant Price, which had taken off at 10:35. The Bristol landed back at base at 13:00 and was rendered U/S by the fire of intercepting CR.42s.

On 6 June 1942, four MC.200s from the 94^a Squadriglia strafed three armoured cars and a truck near Gabr el Abidi, but three were hit by AA, although all reached their home base safely. The damaged MC.200s were flown by Capitano Orfeo Cecchet, Sergente Maggiore Billi and Sergente Alessandro Ruzzene, which all were safe.

During the war, Billi was commissioned.

After the Italy surrendered to the Allies on 8 September 1943 he joined the Italiana Aeronautica Nazionale Repubblicana (ANR) and I^o Gruppo Caccia.

In November 1944 Italian pilots were training on Bf 109s. During this time Maggiore Adriano Visconti was contacted by the OKL, which proposed the training of a group of Italian pilots on the Me 163 Komet in preparation for the probable allocation of this rocket-powered interceptor to the Italians. This was an irresistible offer and Visconti asked for volunteers. Only single men were allowed since the training was so hazardous and seventeen pilots were chosen.
The pilots involved were: Capitano Giuseppe Robetto, Tenente Gian Mario Zuccarini, Tenente Lucio Stramese, Tenente Giuseppe Biron, Sottotenente Aurelio Morandi, Sottotenente Raffaele Marzocca, Sottotenente Franco Storchi, Sottotenente Roberto Di Lollo, Maresciallo Luigi Jellici, Maresciallo Silvio Girolami, Maresciallo Billi, Maresciallo Romano Spazzoli, Sergente Maggiore Gino Pizzati, Sergente Maggiore Mario Veronesi, Sergente Maggiore Giampiero Svanini, Sergente Maggiore Isonzo Baccarini and Sergente Dante Toselli.
Under the command of Capitano Giuseppe Robetto, Second-in-Command of I^o Gruppo Caccia, they transferred during early December to Rangsdorf (Berlin) where they were to train on gliders between 5 to 30 December. The gliders used were the two-seater Kranich, the single-seater Grunau and the Habicht 14, 8 and 6 (the number indicates the wing-span in meters). The Habicht 6 was similar in handling to the Me163 during un-powered flight.
After almost three hours of gliding, the Italians were transferred from Rangsdorf to Liegnitz were they finally saw the Komet for the first time. However bad weather and the Russian advance didn't allow any of the Italian pilots to ever fly the Me163 and the pilots returned to Italy at the beginning of February 1945.

In March 1945 he served in the 3^a Squadriglia of the I^o Gruppo Caccia.

On 14 March 1945, Maresciallo Billi crashed with Bf 109G-10 (W.Nr. 491325/3-2) while landing at Malpenza after a combat with B-25s from the 321st BG with an escort of P-47s from the 346th FS, 350th FG, which had attacked a rail bridge at Vipiteno (Bolzano). His Messerschmitt hit the crane recovering the remains of Bf 109G-10 flown by Capitano Guido Bartolozzi (CO 3^a Squadriglia), which had crashed previously during the scramble. Billi s aircraft lost a wing, cartwheeled to a halt but he was miraculously unhurt.

Billi ended the war with 1 biplane victory.

Claims:

Kill no.	Date	Time	Number	Type	Result	Plane type	Serial no.	Locality	Unit
	1940
	11/06/40		1/7	Blenheim (a)	Shared destroyed	Fiat CR.32		El Adem area	94a Squadriglia
	11/06/40		1/7	Blenheim (a)	Shared destroyed	Fiat CR.32		El Adem area	94a Squadriglia
	11/06/40		1/7	Blenheim (a)	Shared damaged	Fiat CR.32		El Adem area	94a Squadriglia
	11/06/40		1/7	Blenheim (a)	Shared damaged	Fiat CR.32		El Adem area	94a Squadriglia
	11/06/40		1/7	Blenheim (a)	Shared damaged	Fiat CR.32		El Adem area	94a Squadriglia
	11/06/40		1/7	Blenheim (a)	Shared damaged	Fiat CR.32		El Adem area	94a Squadriglia
1	22/10/40	11:25-12:45	1	Wellington (b)	Destroyed	Fiat CR.42		North Africa	94a Squadriglia

Biplane victories: 1 and 2 shared destroyed, 4 shared damaged.
TOTAL: 1 and 2 shared destroyed, 4 shared damaged.
(a) Claimed in combat with Blenheims from 45 Squadron. The 92^a and 94^a Squadriglie claimed two bombers shot down and four damaged for two fighters damaged. 45 Squadron lost three Blenheims and got two more damaged; L8476 crashed into the sea killing the crew, L8519 was damaged during the raid and crash-landed at Sidi El Barrani where it burst into flames killing its crew and L8466 suffered an engine failure over the target, the other engine failed after 100 miles during the return journey eastwards and the plane force landed near Buq-Buq. The crew was rescued by while the aircraft was later recovered and repaired.
(b) Blenheim T2063 of 113 Squadron piloted by Sergeant Price, which landed back at base and was rendered U/S.

Sources:
2^o Stormo - Note storiche dal 1925 al 1975 - Gino Strada, 1975 USSMA, Rome, kindly provided by Ludovico Slongo
A History of the Mediterranean Air War 1940-1945: Volume Two Christopher Shores and Giovanni Massimello with Russell Guest, Frank Olynyk & Winfried Bock, 2012 Grub Street, London, ISBN-13: 9781909166127
Air War Italy 1944-45 - Nick Beale, Ferdinando D'Amico and Gabriele Valentini, 1996 Airlife Publishing, Shrewbury, ISBN 1-85310-252-0
Diario Storico 92^a Squadriglia C.T. kindly provided by Ludovico Slongo
Diario Storico 94^a Squadriglia C.T. kindly provided by Ludovico Slongo
Elenco Nominativo dei Militari dell’ A. M. Decorati al V. M. Durante it Periodo 1929 - 1945 1 Volume A - L
Fighters over the Desert - Christopher Shores and Hans Ring, 1969 Neville Spearman Limited, London
Il Fiat CR 32 poesia del volo - Nicola Malizia, 1981 Edizioni dell Ateneo, Roma, kindly provided by Ludovico Slongo
L 8^oGruppo caccia in due conflitti mondiali - Giuseppe Pesce, 1974 S.T.E.M. Mucchi, Modena, kindly provided by Ludovico Slongo
L aeronautica Italiana nella Seconda Guerra Mondiale I volume - Giuseppe Santoro, 1966 Second Edition, Editore Esse, Milano-Roma, kindly provided by Ludovico Slongo
The Bristol Blenheim: A complete history Graham Warner, 2002 Cr cy Publishing Limited, Manchester, ISBN 0-947554-92-0
The Desert Air Force - Roderick Owen, 1948 Hutchinson, London, kindly provided by Ludovico Slongo
The Desert Air War 1939 1945 Richard Townshend Bickers, 1991 Leo Cooper, London, ISBN 0-85052-216-1, kindly provided by Ludovico Slongo
Additional information kindly provided by Ludovico Slongo