41.   If a return flight on Tuesday rather than the weekend cuts the ticket price in half, parents are likely to go for it.

42.   If he contends or wins, he may arrive in California fresh off a cross-country flight on the morning of the competition.

43.   If you have to book a flight on short notice during this season, be prepared to pay full fare.

44.   In a society with a six-day workweek, flights on Friday nights or Saturdays are the first preference of the secular vacationer.

45.   In addition, luggage that has been checked for a connecting flight on another carrier will have to be rechecked.

46.   In the future, passengers will have fewer choices, as airlines run fewer flights on popular routes and eliminate service on marginal ones, industry people say.

47.   In the final phase of experiments, melatonin will be tested in flight on the astronauts on that mission.

48.   Investigators say that they are also beginning to learn more about how the hijackers operated on the flights on the day of the assaults.

49.   Investigators are reviewing whether any of these pilots were booked on flights on Tuesday.

50.   It also flies to St. Petersburg, which is a short flight on a route served by another good carrier, an Aeroflot offshoot called Pulkovo.