Bats are not the same all over, but here in New Jersey they are mostly insect eaters, not likely to bother people in the slightest. You may have watched them with pleasure without realizing it. An hour or two before dusk, especially in warm weather, if you see “birds” with relatively chunky bodies changing direction in flight every few seconds, you’re probably watching bats go after one insect after another. You’re likely to hear a lot of chirping that does not sound quite right for birds as well. (Only SOME bat sounds are too high to hear.)
If you would like to attract bats to your property, consider building bathouses, as described in the Adobe Acrobat document on this web page.