Assuming UFOs exist, would they be likely to have crashes and mishaps?

Our current airplane technology is pretty good – thousands of flights a day, with (thankfully) very few incidents. Yes, there is the occasional crash – sometimes human error and sometimes failure of parts or equipment. But generally the technology is pretty good.

Now picture a UFO. It must be, by definition, pretty sophisticated technology to make the trip from wherever. But it was assembled by something intelligent, no doubt, whether they were people or some other species.

But if it were assembled and flown, then do we also assume that it is in some way breakable? Would it be susceptible to pilot error? Would parts wear out? Could a UFO crash? (infrequently, like an airplane)

If so, shouldn’t we have found some wreckage? (besides Roswell)