July 23, 2025: The June 13th Israeli airstrikes on Iran were followed up with seven American B2 stealth bombers using fourteen 13 ton ground penetrating bombs to destroy well protected Iranian nuclear weapons facilities at Fordo, Natanz and Isfahan. This did significant damage to the Iranian nuclear weapons program and was a relief to Israel and the United States. Iran had long planned to destroy Israel with one or two nuclear weapons. That program has been delayed several times by Israeli or American airstrikes. Apparently, this policy will continue for as long as it is needed.

The United States will also continue to develop heavy bombers, an aircraft type that the Americans have been building and using since the 1930s. First came the 19-ton B-17, which was developed during the 1930s and entered service in 1938. By the end of World War II in 1945, nearly 13,000 of these aircraft were built. During the war B-17s dropped 43 percent of the 1.5 million tons of bombs used against German military and economic targets. B-17s continued to fly, largely in non-military roles, into the 1950s. As of 2025 four are still flying and dozens more are intact but grounded. Serving on a B-17 crew was dangerous and casualty rates were higher than those in the infantry. About 88,000 heavy bomber crew were killed over Europe, most of them on B-17s.

A less successful heavy bomber was the B-24. Some 8,000 of these were built because they had longer range, heavier bomb load and proved invaluable in the war against German submarines in the Atlantic and as a long range patrol, bomber and transport aircraft in the Pacific. The last active B-24, used by the Indian air force, retired in 1968.

The most expensive bomber of World War II was the 60-t0n B-29. Two of these dropped atomic bombs on Japan in 1945, the only aircraft, so far, to ever do so. Development and production of 3,900 aircraft cost about $3 billion, which is 53 billion in 2025 dollars. An updated version, 370 0f the 78-ton B-50, entered service in 1948 and were retired in 1965 after many of them served in non-combat roles.

In 1946 the 185-ton B-36 entered service. Powered by six propellers and four jet engines, only 385 were built and they served as the primary U.S. heavy bomber until 1959.

In 1951 the 100-ton B-47 entered service. While 2,042 were built, the last of these was retired in 1977.

In 1952 the first of 742 221-ton B-52s entered service and are expected to serve until 2050 or later. A very effective and adaptable design, 76 are currently in service.

In 1960 the less successful 80-ton B-58 entered service. Only 116 were built and it was retired in 1970 after only ten years of service. Reliability problems were the main reason, and 21 percent were lost to accidents.

In 1997 the first 170-ton B-2 entered service. This was the first stealthy heavy bomber. That came at a cost, which was $2 billion each. Maintenance and operation was also very expensive. Congress would not pay for the 132 the air force wanted. While only 21 were built and 19 are still operational in 2025. In the 2030s the B-2s will gradually be replaced by the B-21.

The 81-ton B-21 is still in development and three of the eventual 100 aircraft exist. The first flight was November 2023. This is a much improved B-2, designed to quickly travel to targets anywhere in the world on short notice. These B-2s recently demonstrated this in Iran. B-21s will cost at least $800 million each and over a billion before 30 or more years of service are over. It is hoped that the B-21 can eventually replace the B-2 and B-52 by 2050. Australia plans to obtain some B-21s and provide base and maintenance capabilities for American B-21s.