Even before it lost the CX-HLS contract, Boeing was asked by Juan Trippe, president of Pan American World Airways (Pan Am), one of their most important airline customers, to build a passenger aircraft more than twice the size of the 707.
Čak i prije nego je izgubio CX-HLS ugovor, Boeing je pritisnut od predsjednika Pan American World Airwaysa ( Pan Am-a) kao najvažnije aviokompanije kupca, da izgraditi putnički avion više od dva puta veći od 707.