How did these reputedly desperately poor folks like Clinton and Obama have the dough for world travel?
Back when plan tickets were not commodity items....
There were grants from such outfits as the American Friends Field Service (way Left), various government programs, courses one would take where airfare and lodging was included. E.G., I studied French one summer at Montpellier --- a 9-week course --- transportation, room and board, tuition, $380! And there were funding sources aplenty to cover that through your school, or DoS programs etc. etc.
Your real question is who funded the kids who wound up "behind the Iron Curtain?" (I could name some names, but then we would have to shoot you.)
The other thing to remember was that Room, Board, and Tuition at my very fine college was around $3,000 a year. Two years when I wasn't traveling, I managed to save up more than half of that amount working over the summer.
It was an entirely different world.
Clinton's Uncle Ray was the political boss of Hot Springs, AK and was very well connected. When Ms. Virginia Kelly turned up enceinte by her BF in Louisiana, it was Uncle Ray who arranged the paperwork for her marriage to the dead guy in the ditch, Mr. Blythe from Texas.
Of course he was already married in Texas, and with kids, so Uncle Ray had to fix him up with an ex-post facto divorce. Then it turns out, Blythe was in the army in Europe until a couple of months before Bill's miraculous "pre-mature birth at 9+ pounds. Not to worry, Uncle Ray handled that,too. Bill's step-dad worked for his brother's big GM dealership which covered the seamy side of things and allowed Bill and brother Roger to cavort at the local country club. He wasn't hurting for money, either.
Neither of these boys were Log Cabin material.