Washington ? Largely because of Sept. 11, the number of airline fatalities in 2001 was the highest in 24 years, the National Transportation Safety Board reported Tuesday.

The safety board said 531 people died in crashes on U.S.-scheduled airlines last year, the highest yearly total since 1977, when 582 people were killed in the crash of two Boeing 747s collided on a Canary Islands runway.

All 265 passengers and crew members aboard four hijacked airliners were killed Sept. 11. Terrorists crashed two of the planes into the World Trade Center in New York City and one into the Pentagon near Washington. The fourth plane crashed in a Pennsylvania field.

Another 260 passengers and crew members died two months later when American Airlines Flight 587 crashed shortly after takeoff from New York’s Kennedy Airport. Five people on the ground also were killed.

In addition, one airport ground worker was struck by a propeller last August.

The 265 deaths on Sept. 11 were the most from a terrorist attack on aviation since Dec. 21, 1988, when 270 people died in the bombing of Pan Am Flight 103 over Lockerbie, Scotland, safety board statistics show.

The 1977 crash in Tenerife, Canary Islands, indirectly involved terrorism. A KLM plane that had been diverted from Las Palmas, its original destination, because of a bomb explosion crashed as it took off for an onward flight from Tenerife into a taxiing Pan American 747.