if memory serves me, in about 1991 Nature, the scientific journal, ran a front cover and article about bumble bees, and in particular about the "they shouldn't be able to fly" thing, and their writer said it was urban myth, that they couldn't find any report in any credible journal stating this factoid. The paper did report that they used less fuel in hover mode than in level flight, which is a neat trick. Actually, just measuring fuel burn for a bee is tricky.