Many years ago I had an aged (10 years younger than I am now!) Spec Air Sqn Ldr (initials DH) working for me. Went through his logbooks when he retired to find some "dits" for his retirement do.
Like many of his generation, he started flying in late 40s early 50s on Meteors then Hunters (including a Meteor in the Coronation Flypast - 600+ aircraft, all UK based!). I noticed a small number of Sabre hours; mindful he had never been on a Sabre Sqn, asked the background.
DH: "That was an exchange visit with USAF in Germany - a proper exchange: we flew their jets and they flew ours"
Moi: "But there were no two-seaters .......???"
DH: "No, they helped us start it up leaning in the cockpit, and left us a kneepad with useful speeds and limits. Then we got airborne and 'mixed it' with them flying ours and us flying theirs ..........!!"
An' ye tell that to young folk today ...........