I'm with Fuji - for most people flying is a means to an end - they've got to want to get somewhere to get in an aeroplane.
With my other half I purposely didn't ask her, but started doing trips I thought she'd enjoy and waited for her to ask to come along. One sunny Sunday I went to Shoreham and lay on the beach for a couple of hours. The next weekend I flew to Norwich and went round to her mum's for a cup of tea (excellent
PR!). A couple of weekends later when I mentioned I was off to Le Touquet for the day she was dead keen to come along.
As it happened, she was REALLY nervous on the flight out - and I think if that had been the only flight she would never have come again. Inevitably though, we had to get back from Le Touquet and by the end of the second flight she was a lot more relaxed. Now she tends to fall asleep on climbout and wake again on finals.