Time for a post Superbowl clue:
1) These two aircraft shared a distinction from all other aircraft
2) While both types had great combat records, one was the first and the other the last
3) The two aircraft had maiden flights approximately four years apart
4) The two aircraft made their first combat flights approximately nine years apart
5) The two aircraft were involved in events that led to the loss of the first but not the second
6) Only the aircraft that was lost had more than one person on board.
7) The "last" aircraft was performing a function it was never designed to perform
8) The "last" aircraft was replaced soon after by new, faster aircraft that were themselves in service for well over 30 years
9) The last of the "first" was retired by the air forces of the building nation after only eight years of service
10) Both the "first" and the "last" had a disadvantage in their similar events, the "first" wasn't able to overcome this while the "last" did
11) The aircraft involved all used different engines
Good Luck