The airplane used in the filming was loaned out by Hans Otto Meyer, a Norwegian financier and shipping magnate. The cast was invited to his villa for a party and McShane and Connery were given a tour of what turned out to be a secret weapons cache for the Norwegian Stay Behind army. A few years later, Meyer was arrested and the government was alerted to the existence of a secret army that only a few government officials had been aware of previously.
The aircraft displayed in the hijacking is a Boeing 737-200 in the livery of Mey-Air. Mey-Air, a Norwegian charter airline that operated from 1970 to 1974, was owned by and named after shipping owner Hans Otto Meyer. Filming started in January 1974. During production, Mey-Air defaulted on their payments to Boeing for the aircraft. Boeing sent representatives to Fornebu, Norway, to repossess it on February 26. Filming of the aircraft shots was never completed.
The little boy coming out of the toilet in the airplane keeps saying "bæsj" to one of the terrorists, who mimics the boy's word. Bæsj is the Norwegian word for shit.
Several of the local actors' voices were dubbed over by familiar sounding British voice-over actors.
The watches containing the detonators for the bomb used by the terrorists on the plane, are Omega Speedmasters.