Are you kidding? He's a 21 year old adult! Some people his age have already two kids, paying mortgage/rent, flying on his one etc. I am sure he had gone to many unfamiliar places in Israel or other cities already....
Not all people are the same.
I have two sons who went to Yeshiva in Eretz Yisroel. I sent each on of them alone the first time they went. Totally different experience, totally different attitudes.
I just dropped off my son at JFK on AB flight (he likes that one because TXL is only 20-25 minutes from Chabad, where he can go to mikvah and daven), yet he still had my DW escort him up until security. My older son has gone through various airports alone, took public transportation, almost always made his connecting flight only at the last moment, and manages. Forgot to mention that the one son calls home a few times a day, other son we were at his mercy and were lucky if he called once a week to say good Shabbos.