I ran a small travel budget in Malaysia for 2 years. I would invite SME's out to lecture on various courses. I would provide economy class travel (return) and the losing unit had to pay for any upgrade and the Hotels/allowances etc. The RAF was the only contributor that upgraded personnel to Club Class (all ranks as well). Personally, they should have. 14 hours each way with a fairly tight schedule in between justified the expense. The Kiwi's and Aussies all went cattle.
IIRC the USAF always travel cattle as well. We used to send them glasses of champagne when travelling on NATO Tacevals.
Following on from Beagles comment. I remember one particular 2 star who travelled with wife. He was entitled to club class tickets. He went 1st Class and the wife was put in Economy.
The fact that travel by air now has to be signed off by a Gp Capt at least is a sign of the times. My last day in the RAF is 30 Nov this year. A great 25 years but I am counting the days, minutes and seconds.