The war fought in the air during the Vietnam War was decisively in favour of US forces. America's air power dwarfed North Vietnam's and, in theory, such dominance should have had a decisive say in the outcome of the Vietnam War. There were those in America who supported the idea of simply bombing North Vietnam to destroy the country - Curtis LeMay stated that the US should reduce North Vietnam to rubble. The 'hawks' in the White House would have been sympathetic to this.
America's air power had three bases. There were US bases actually in South Vietnam such as the one at Danang. A variety of planes flew from US carriers based in waters off the shores of North Vietnam while the huge B-52 bombers flew from bases in Thailand and Pacific Islands such as Guam.
At the start of the bombing campaign against the North, President Johnson wanted restraint and caution. He had gone into an open war with the North based on the aggression of the North Vietnamese government and he wanted the world to see that America held the higher moral ground. This would have been lost if there had been indiscriminate raids on the North which resulted in the loss of civilian life. As it became clear that the bombing of military targets was not stopping the North Vietnamese government from supplying the NLF, the number of targets that could be bombed was increased to include bridges, rail lines and other communication systems. Even this did not stop the North, and it was then that the US turned to saturation bombing using her fleets of B-52 bombers. These planes flew at a height whereby they were reasonbly safe from attack. They carried a variety of bombs but the most common was high explosive. These bombs could leave a crater thirty feet across and deep. If anyone was out in the open while a bombing raid took place, the shock wave of these bombs would knock an individual senseless if they were less than 1 kilometre from an explosion.
America's primary targets in the North were the cities of Hanoi and Haiphong. Both were heavily defended and while B-52 bombers were reasonably safe as they flew so high, lower flying bombers or fighter-bombers were less safe. Between 1965 and 1968 over 1,400 US warplanes were shot down over North Vietnam with many of these aircraft were involved in raids on either Hanoi or Haiphong. The North Vietnamese had Russian-supplied Mig-17 and Mig-21PF fighters. However, most damage was done by anti-aircraft guns on ground level. Russian SAM's (surface-to-air missiles) were less effective due to the counter-measures on board US planes that allowed the US pilots to evade them.
To provide the civilian population with some form of protection, the North Vietnamese government built thousands of small air raid shelters (many just big enough for one person) in Hanoi. As with the example of London during the Blitz in World War Two, the more America bombed the North, the greater the resolve of the people:
“The Americans thought that the more bombs they dropped, the quicker we would fall to our knees and surrender. But the bombs heightened rather than dampened our spirit.”