Page "Bomber" Paragraph 27

The development of large strategic bombers stagnated in the later part of the Cold War because of spiraling costs and the development of the Intercontinental ballistic missile ( ICBM ) – which was felt to have equal deterrent value while being much more difficult to intercept.

Because of this, the United States Air Force XB-70 Valkyrie program was cancelled in the early 1960s ; the later B-1B Lancer and B-2 Spirit aircraft entered service only after protracted political and development problems.

Their high cost meant that few were built and the 1950s-designed B-52s continued in use into the 21st century.

Similarly, the Soviet Union used the intermediate-range Tu-22M ' Backfire ' in the 1970s, but their Mach 3 bomber project came to naught.

The Mach 2 Tu-160 ' Blackjack ' was built only in tiny numbers, leaving the 1950s Tupolev Tu-16 and Tu-95 ' Bear ' heavy bombers to continue being used into the 21st century.