Increasingly rarely it seems. The US has all the best toys and no-one else wants to play any more.

The F14 scored 130 kills… for the Iranians. The F15 has an impressive 100-0 kill ratio (mostly by Israel); zero air to air losses, but 175 losses to accidents.

F16’s have about 60 kills (almost all by Israel again, they really love American jets).

F18 two kills, I think.

Soviet airframes are pretty much the same. Almost all their kills are in the hands of Middle Eastern third parties (Syria, Egypt, Iraq).

These are wars from decades ago, and we don’t have any modern examples of large scale air combat, or of combat that wasn’t highly one-sided. F22’s have hardly ever been used, and I wouldn’t be surprised if the same happens with the F35. Too damned expensive to take out of the box.

Yes. Quite a lot. A small number at the end of the second world war. Regular use of machine-gun armed jets during the Korean War. The Vietnam war saw jet fighters armed primarily with missiles engaging each other (195 kills claimed by the US). Various conflicts in the middle east including the The Six Day War, the Yom Kippur War, the Iran-Iraq war (around 100 kills claimed by Iran) and The Gulf War (44 claimed kills by the US). And many more conflicts as well. The most recent US air to air kill was in 2017. An F-18 shot down a Syrian SU-22. Russia also claims some air to air kills in Ukraine. Jets have gone toe to toe with each other since the moment they were first introduced continuously until the present day. The total number of air engagements is somewhere on the order of magnitude of 1,000, and a fair bit less if you are only considering fighter aircraft