This is a kinda of things that I always liked when I was spotting at Lisbon, Faro or even abroad, see delivery flights passing by. In Lisbon although was not common sometimes you could see so really good ones. One of the first that I remember was a B. 727-030 ex: Lufthansa passing via Lisbon to VASP of Brazil, the reg. was PP-SRY and it was quite a smash. Another time I saw in Lisbon airport 2 metal shinning L100 Hercules with american registration, sudenly a vehicle arrived close to one L100 at the time and changed registration at that same moment, one L100 was registred D2-THA latter for TAAG Angola and the other was registred D2-EAS for Angola Air Force, that was very exciting!!! Not going very deep I just recall for example 2 ATL98 Carvair passing via Lisbon to Falcon Airways, a Britten Norman Defender in delivery flight to Botswana, a Fokker F-27 to Sonangol of Angola. Outside I remember once at Heathrow seeing a Kuwait Airways 727-200 on delivery flight!
CV990, the Maserati of the skies!