The Refresh ones are okay, but my doc specifically recommended another brand because he knows I'm on planes a lot this time of year. I've flown several times now with the TheraTears brand single use preservative drops. Inside the box, the drops are in foil packs (4 per pack). I fly with one pack opened, and all the other packs sealed. I've never been questioned about it at all.
By the way, my Lasik was three months ago and the first flight was within a month of the procedure.