and a bunch of fighters, too. At some point, their defenses would've been saturated but I suspect that was a pretty high point. As for building in countermeasures into the V-1s, that would've added a lot of complexity to their guidance system (it was essentially a dead-reckoning system that flew in a particular direction for a specified distance.) Throw in weaving maneuvers and the already inaccurate weapons would've become even less accurate without some more sophisticated guidance system.

The Germans did use air launching of V-1s towards the end of the war. According to this source:

Even though the launch sites were overrun, flying bombs continued to hit England, if in reduced numbers. Back in early July, a small number of flying bombs hit Manchester and Gloucester. Allied leadership was baffled as to where these attacks were coming from, since the range of the V-1 was roughly known, and there was no place near enough for the Germans to set up launch sites that could reach these targets.

As it turned out, the Germans were launching the flying bombs from specially modified Heinkel He-111 bombers, operating from airfields in the Netherlands. Work on this scheme predated the beginning of the flying bomb blitz, and involved removing the He-111's bomb racks and a fuel tank, and installing launching gear and provisions for carrying a V-1 nestled under the left wing. The modified bombers were given the designation "He-111H-22". This proved to be a risky business, since the flying bomb was very heavy and could be lethally tricky to launch. 1,200 V-1s were launched in this fashion, with the loss of 77 bombers. Twelve bombers were lost on two missions alone simply due to the premature detonation of the V-1's warhead after the He-111 left the runway.

Air launch was abandoned in mid-January 1945, due to the high attrition and the advance of Allied forces. However, the Germans were not quite done with this game, having developed a new version of the V-1 with a range of 400 kilometers (250 miles) by reducing the size of the warhead and increasing the size of the fuel tank. They launched about 275 of these long-range flying bombs against Britain from the Netherlands in March 1945. British defenses were able to adjust to these last-gasp attacks, and the looming defeat of the Reich ended the campaign for good at the end of March. V-2 rocket attacks against England, which had begun in September 1944, slowly fizzled out as well.