No personal experience here BUTT maybe check with the docs
to see if something like daily low dose aspirin ( 81 mg ASA ) would be safe for him ????
Also getting up and moving around a lot is important.
Stay well hydrated and avoid alcohol on the flights.
Be vigilant about "personal hygiene" i.e. using sani wipes and even a face mask may not be too over the top,
IF the docs think there is any issue with lowered immunity post chemo ???
( we have local travel expert here who saniwpies EVERYTHING around her plane seats when travelling )
Is he able to have a flu vaccine ? as you will be travelling into the start of the fall flu season.
Not trying to be alarmist here ... just thinking of things which could impact your travels adversely
Congrats on the good news of his responses so far !
Best wishes on your trip(s)
((p.s. how is that X Factor thing going !!!!! ))
Cheers and Harmony
CRguy on the Journey