I am looking at United flight to join Greece tour. Aegean Airline is a star alliance member offering lower fares on the United website. The return from Greece leg would be Aegean airline from Greece to Heathrow with a 2 hour layover to go back to US. Can anyone comment on Aegean airline and/or the 1 hr 50 minute layover at Heathrow ( whether time is sufficient)? Do we have to go through immigration control at Heathrow coming from Athens back to the US?
Thank you.