August 22, 2025: The June 13 Israeli airstrikes on Iran were followed by seven American B-2 stealth bombers using fourteen 13-ton ground-penetrating bombs to destroy the well-protected Iranian nuclear weapons facilities at Fordo, but not at Natanz or Isfahan. This caused significant damage to Iran's nuclear weapons program, delaying the completion of a nuclear weapon by approximately six months. However, this assumes no further attacks by the Americans or Israelis, which are likely to occur.

The destruction of the Fordo program was a relief to Israel and the United States. Iran had long planned to destroy Israel with one or two nuclear weapons. This program has been delayed several times by Israeli or American airstrikes, a policy that will apparently continue as long as necessary.

The United States will also continue to develop heavy bombers, a type of aircraft it has been building and using since the 1930s. First came the 19-ton B-17, developed during the 1930s and entering service in 1938. By the end of World War II in 1945, nearly 13,000 of these aircraft had been 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 remain intact but grounded. Serving on a B-17 crew was dangerous, with casualty rates higher than those in the infantry.

A less successful heavy bomber was the B-24. Some 18,000 were built due to their longer range and heavier bomb load, proving 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, was retired in 1968.

The most expensive bomber of World War II was the 60-ton B-29. Two of these dropped atomic bombs on Japan in 1945, the only aircraft to do so thus far. Development and production of 3,900 aircraft cost about $3 billion, equivalent to $53 billion in 2025 dollars. An updated version, the 78-ton B-50, saw 370 units enter service in 1948 and was retired in 1965, with many serving 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, serving 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 was retired in 1977.

In 1952, the first of 742 221-ton B-52s entered service and is expected to remain in use until 2050 or later. A highly 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 just ten years due to reliability problems, with 21 percent lost to accidents.

In 1997, the first 170-ton B-2 entered service. This was the first stealth heavy bomber, costing $2 billion each. Maintenance and operation were also very expensive, and Congress would not fund the 132 aircraft the Air Force requested. Only 21 were built, with 19 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, with three of the planned 100 aircraft completed. The first flight was in November 2023. This is a much-improved B-2, designed to rapidly reach targets worldwide on short notice. The recent B-2 strikes in Iran demonstrated this capability. B-21s will cost at least $800 million each, likely exceeding $1 billion over their 30 or more years of service. It is hoped that the B-21 will eventually replace both the B-2 and B-52 by 2050. Australia plans to acquire some B-21s and provide basing and maintenance capabilities for American B-21s.