Duty free goods will be available for purchase though the choice may be limited on certain flights.

An airline may therefore schedule a certain flight at a loss if there is another overriding purpose.

Other airlines followed, although some are swallowing the charge on certain flights to stay competitive.

Numerous astronauts have noted that only when reading this book did they learn why they had been selected for certain flights decades earlier.

They also have capacity controls, so certain flights may be virtually impossible.

Still, the longer waits will cause some travelers to reconsider taking certain flights, like those for weekend jaunts or short business trips.

Pan Am promised a free flight to anyone with a valid complaint about service in first class on certain flights.

He ordered that federal law enforcement officers be deployed to act as security officers on certain high-risk flights.

The hijackers in the 1995 plot carefully analyzed commercial air routes before targeting certain flights for attack, investigators said.

American Airlines' plans to offer in-flight broadband access across certain transcontinental flights took a major step forward yesterday.