I have to agree with Peachfront- if you have not traveled on a big time trip with these friends- I would make some "dry runs" i.e. short week end trips- so see if you want to spend 10 days and thousands of dollars with them- or some of them - or none of them. From expierience- I would choose very carefully who you take a "trip of a lifetime" with. It could be the greatest trip you ever have taken- or worst.- I would be careful.
To the air travel- I travel to conferences and some educational seminars- with one gal- we have traveled twice a year- for over 15 years- she is a "gold"- I am a mvp- so she gets first class upgrades before me- if we are on a long flight- over 3 hours- she will attach my ticket with her- and we both get upgraded- but if I am in coach and she is in first- we get there at the same time. No big deal to either of us. We have always discussed all this fully. rlb