01.04.1939 Maiden flight of Mitsubishi A6M1, the famous Zero. The Zero was the first monoplane with enclosed cockpit and retractable undercarriage put in service in Japan, and was a very nasty surprise for the allies. Mitsubishi A6M Reisen/Zeke/Zero/Rufe
01.04.1954 Last RAF Spitfire sortie, a photo-reconnaissance Spitfire Mk.19 flew over Malaya seeking for insurgent positions. Supermarine Spitfire
01.04.2001 US Navy recce aircraft EP-3 Aries II flew spy mission over Chinese islands 104 km east-south from Hainan Island. PLAAF J-8 fighter intercepted US aircraft, but she rammed Chinese fighter. Chinese pilot dead. Lockheed P-3 Orion Shenyang J-8