Many top executives who fly say the "friendly skies" are not always friendly, especially when delays cost them substantial amounts of money and time, a survey of nearly 500 U.S. company leaders shows.

The survey included members of The Executive Committee, an international group for corporate chief executives and presidents. Members were questioned about safety in the skies, on-time travel and whether flight safety was improving.Thirty-six percent of the executives said they had lost job efficiency due to flight delays. In the last month, the average time lost was five hours.

Nine percent said delays had cost them money or sales, with the average loss estimated at $8,000.

More than a third of the surveyed executives said they had been either bumped from their seat due to overbooking or had experienced lost luggage during the past year.

A large percentage - 83 percent - had been grounded for reasons other than bad weather. They said this happened about 19 percent of the time in which they flew. The average delay was almost three hours.

The executives also indicated concern about air safety. A slim majority called the skies safer or as safe as five years ago, but almost 47 percent said the skies were not as safe.

In rating air carriers, American Airlines placed No. 1 in the survey, cited by 29 percent of the executives. Next came Delta Airlines and United Airlines, cited by 22.4 percent and 22 percent, respectively.