The large aircraft in the background on the movie poster appear to be multiple Boeing B-52 Stratofortresses, which did not enter active service in the U.S. Air Force until 1955, several years after the movie takes place (1952). Also, the mission is specifically assigned as a single plane mission because of the accuracy required in the bombing of the target.
The main aircraft on the movie poster is a Martin B-57 Canberra, which is not featured in this movie and had not even flown for the U.S. Air Force (July 1953) at the time it was supposed to take place (1952). They were, however, in service when the movie was released, in 1955.