"If they are paying attention, passengers will notice a much smoother ride," he said.

Except for a new advertising campaign that United began tonight to publicize the deal, passengers will notice few changes.

Over the long term, passengers could notice a difference in routes and schedules.

He let the other car get out of sight before its passengers could notice the cab behind.

The other passengers may notice on some level that the crying has stopped, but they never try to find out why.

A few passengers noticed, crew members said, but most were oblivious.

They've been working on the railroad, and the passengers have noticed.

For now, passengers will notice little if any difference when travel agents book through the lower-cost systems.

It will be some time before passengers notice changes in the building.

Of course, passengers will notice when a flight is canceled.