Camouflage began to reappear on USAF aircraft during the Vietnam War, and this led to a change in tail number presentation. The letters "AF" were added directly above the last two digits of the fiscal year, followed by the last three digits of the sequence number. The three-digit sequence number has a height of the AF and fiscal year letters combined and is sometimes called the "large" component of the tail number. For example, F-4E serial number 67-0288 had the tail number 67(small) 288 (large). This could of course lead to confusion, since aircraft 67-1288, 67-2288, etc would have exactly the same tail numbers as 67-0288 under this scheme. This would not ordinary cause a whole lot of difficulty unless of course some of these larger serial numbers also happened to be F-4Es (which they were not). Unfortunately, the system was not always consistent--for example F-4D serial number 66-0234 had a tail number that looks like this: 60(small) 234(large). It appears as if this number was obtained by omitting the first digit of the fiscal, and combining the remaining "6" with the "0234". Consequently, one often has to do a lot of educated guessing in order to derive the aircraft serial number from a knowledge of its tail number, and a knowledge of the aircraft type and sometimes even the version is required. I would appreciate hearing from anyone who has noted different tail number presentations on recent USAF aircraft.

However, Air Mobility Command and USAF Europe aircraft still display the previous format for the tail number, with all digits being the same size and the first digit being the last digit of the Fiscal Year and the remaining 4 digits being the last 4 digits of the sequence number. There is no AF displayed, just the name of the command a couple of feet above it. However, there are some exceptions--for example the tail number of 64-14840 is 14840, not 44840. Both of the fiscal year digits were omitted.