I haven't flown in a couple of years, so this should be interesting now that they've reacted to the last few threats, I mean beefed up security.
The only way to "ensure" perfectly safe air travel is for everyone to have their belongings confiscated upon arrival at a bus depot, thoroughly inspected while all the passengers are summarily stripped and scanned and their clothing placed in clear plastic bags tied to their suitcases. Then all the now-naked passengers will need to be bussed to the air terminal, where they will be scanned and inspected again, to make sure that there were no "terrorist collaborators" traveling together and were able to activate internal proximity bombs. Finally, upon boarding, all passengers will be required to have their hands in the air for the duration of the flight, since all previous attempts at mid-air attacks have involved the hands being out of sight at the time of the attempt.