Which is the most experienced fighter. I believe it is F-16.
assuming you're talking active,
this place has the following information.
F15s (non-Es) 102 kills, no losses
F4 = 306 kills, but 651 losses (it did as much bombing as it did fighting other aircraft, 545 of the losses were from ground fire, almost all of those in Vietnam)
F16=76 kills, 6 losses
Mig21= 240 kills, > 501 losses
So, technically the F4, but nobody is flying them as proper fighters in 2019. There are a few Mig 21s out there mostly in Africa and former Soviet client states that are broke.
In comparison, the Bf 109 had tens of thousands of kills.
