It's probably against the law to annoy residents with audio ads from blimps and for a good reason.

I bet rednecks would shoot their rifles at would be audio ad blimps passing over their property without thinking twice - like they do now with drones. And I don't blame them, because I'd do the same any day.

I'd buy a rifle for that reason myself. Or revive my high-school hobby of building solid fuel rocket engines. I'm just curious what stops ad blimps from appearing in big cities.

I'm pretty sure the audio would fall afoul of noise ordinances. If not, you'd probably hear it from strip malls.

I suspect what stops us from seeing more blimps is cost. They're expensive to operate, and billboards are cheap.