Starting in 1969 and for 5 seasons the USAF Thunderbirds Demonstration Team flew the McDonnell Douglas F-4E Phantom II. This was a move back to the team's tradition of using front-line type aircraft in their performances, something they had gotten away from when they previously flew the T-38A Talon super-sonic trainer. Converting the large F-4E to Thunderbird requirements was the most difficult and extensive in the team's history. The various metals used on the F-4E to combat high heat and friction caused the paint that had been used on previous Thunderbird aircraft to look patchy. Out of necessity a polyurethane based paint was developed that would meet all requirements and provided a smooth looking finish. The main color on the F-4 became white instead of the usual silver of the previous aircraft. The white paint scheme has been used on all the Thunderbird aircraft from the F-4E through to today's F-16.