U.S. commercial and private airplane accidents killed 875 people in 1988, the lowest number this decade, with small planes showing the most improvement, government figures indicate.

The decrease, shown in preliminary figures from the National Transportation Safety Board, came despite steady increases in the number of hours and miles flown and a 30 percent increase in the number of commercial flights over the past decade.The most dramatic reduction was in the number of people killed in small, private plane accidents, down from 1,556 in 1978 to 782. Flying hours for small planes have decreased about 20 percent since then, according to the Federal Aviation Administration.

The next lowest number of fatalities came in 1986, when 1,034 people died in commercial and private airplane accidents. The NTSB figures do not include military crashes.

The 875 total fatalities in 1988 do not include the 270 people killed when Pan Am Flight 103 exploded over Lockerbie, Scotland, Dec. 21, because investigators have determined it was not an accident but an act of sabotage.

They do include two other crashes that received widespread attention. A Delta Airlines Boeing 727 crashed during takeoff Aug. 31 near Dallas, killing 14 people, and a flight attendant was killed when an Aloha Airlines Boeing 737 lost the top of its fuselage before landing near Maui, Hawaii, on April 28.

The board said the accident rate for scheduled airline flights was 0.389 per 100,000 departures, which means that roughly one out of every 257,000 flights resulted in an accident.

The rate for fatal accidents last year was one in 3.6 million flights. The safety board tallied 7.2 million U.S. airline departures in 1988.

Major airliner accidents dropped to 29, from the 13-year high of 33 in 1987, the board said.

Twenty-one people were killed in 20 commuter airline crashes last year, down from 61 fatalities and 34 accidents in 1987. The accident rate for commuter flights dropped by nearly half from 1987.

In general aviation, which includes all small, private plane flights, the number of accidents dropped to 2,332, from 2,471 in 1987. The board said it was a record low since it began collecting statistics and the sixth consecutive annual decrease in the accident rate.