How do bees get lift?

It was once said that the bumble bee is too heavy to fly, but no-one told the bee. This wasn't helped when someone calculated the lift generated by the bee's wings and said it wasn't enough to hold the bee's weight.
The error arose because the person calculated lift treating the wing as a simple aerofoil. It wasn't until some years later that researchers found the truth: As the bee flaps its wings, on the downstroke vortices are created above the wing, and these greatly increase the lift generated -- more than enough t carry the bee.