Going from US to Aruba is super easy. If you do NOT have a return trip scheduled on the same ticket, make sure you have copy of it with you when you check in. Short paperwork into aruba - immigration is usually pretty short, but can be a long line if lots of planes at same time - but not too bad. We always wait on the luggage on the other side so no real delays due to immigration. Customs you just walk out the door. The only people we have ever seen stopped are locals.
Aruba to US is not so easy. Do plan on 3 hours at the aruba airport. Here are the lines:
1. Airline check-in
2. Aruba doc pre-check
3. Aruba immigration departure
4. Aruba airport security
5. Baggage pickup ( a really long line)
6. US immigration and customs (as long as the baggage line)
(drop bags on conveyor belt - no lines)
7. TSA security
Saturday 11/14 - this was approx. 2 hours of constant standing in line, walk to the next line. (It was literally one line from US immigration, that backed up to the baggage line, the baggage line was almost to the aruba security exit, the aruba security line was backed up to the immigration exit. )
There were many calls for passengers to go to their gate as their plane was leaving - leave yourself enough time.