According to this
YouGov poll, 51% of Americans approved of the airstrikes.
Crosstabs are kinda interesting:
Total: 26% strongly support, 25% somewhat support, 16% somewhat oppose, 16% strongly oppose
Democrats: 12% strongly support, 31% somewhat support, 21% somewhat oppose, 20% strongly oppose
Republicans: 54% strongly support, 26% somewhat support, 10% somewhat oppose, 4% strongly oppose
Independents: 22% strongly support, 21% somewhat support, 10% somewhat oppose, 4% strongly oppose
The olds also support this way more than every other age demographic, which isn't surprising.