The principle that should govern all plane-seating situations is the same one that we are to employ in all human interactions, namely, menschlichkeit [i.e. being kind and considerate] not causing people discomfort or harm. Theres nothing wrong with politely asking a fellow passenger traveling alone if he or she minds switching seats. When my wife and I were seated in different rows on a flight to Israel earlier this year, that is what we did, and the two people we asked were happy to accommodate us, allowing us to sit together for the flight. Had we not found people willing to switch, we would have taken our seats as assigned. No Torah-observant Jew has a right to inconvenience another person, nor to flout airline rules about standing in aisles at certain times. Ideally, passengers who are not happy with their seats, for whatever reason, should ask a steward or stewardess for help. If some accommodation can be found, fine. If not, then one is required to sit where assigned (or leave the plane, always an option for someone who decides as a matter of principle to refuse a seating assignment). If someone truly wishes to control who he is seated next to, he or she can purchase two tickets and leave the seat empty.
So, by causing inconvenience and perhaps even embarrassment to others, these men negated the attempt to follow one Jewish law by violating others. I'm sure they were utterly sincere in their desire not to violate the precept of negiah (the prohibition against touching anyone of the opposite gender who is not your spouse, parent, sibling or grandparent---the source of your "no handshaking with a woman" situation), but they should have read up more on not violating other precepts of causing hardship to others. And certainly, by providing grist for the ever-present anti-semitic mills, they also erred.
Thanks for posting that quote.