Aviation Safety Network records indicate that at least 81 passenger aircraft were involved in (partial) explosive device detonation events since 1945.
From the extensive ASN accident database, a list was compiled detailing 81 cases of passenger airplanes involved events in which an explosive device (partially) detonated on board. The majority of these events (60%) occurred during the 1970s and 1980s.
The first suspected case of the use of a bomb in terrorism was the February 1970 bombing of Swissair flight 330 which crashed after takeoff from Zurich, Switzerland, killing all 47 on board. On the same day an explosion occurred in the cargo hold of an Austrian Airlines flight out of Frankfurt, Germany. This flight landed safely.
Until then the motives of most bombings were wither murder or suicide, often with the aim of cashing in on life insurance policies.
More information:
- Interactive world map of aircraft bombings
- Google Spreadsheet with aircraft bombings
- ASN List of Bombing Events (includes 6 military bombings)