5Dropped by
how you get one
The Queen Bee drops them, and she is optional, so plenty of players finish the early game without ever seeing a pair. She is worth going back for. Expert and Master worlds improve the odds noticeably, which is unusual for a mount and means a difficulty run gets there in fewer attempts. Her larva can be found and broken repeatedly in the underground jungle, and she can be summoned deliberately once you have the item for it, so this is a farm rather than a lottery.
how the flight meter really works
The bar is two halves that behave differently. During the first you have proper flight and can hold your altitude indefinitely. During the second the bee tires and you sink at a rate that keeps increasing, though the down key pushes the descent along. After that it needs a few seconds on the ground before it will fly properly again, and the heavy breathing animation tells you when it is done. Take off before that and it will still fly, just badly.
the landing trick everyone gets wrong
Touching the ground restores the first half of the meter instantly, but the tired half only comes back gradually. Bounce off the floor and immediately launch again and you start drifting downward during what should have been your good flight time. In a boss fight that means treating the floor as a reload rather than as a trampoline.
stretching the flight
Anything that weakens gravity extends the air time sharply. A Featherfall Potion roughly doubles what you get, and the thin gravity high above the world does the same, which is how people reach floating islands with no wings at all. Accessories that hand out extra jumps or flight time, a Cloud in a Balloon or a Bundle of Balloons among them, feed the bee as well. Summoning it in midair only costs half the meter, and dismissing and resummoning it buys more time aloft.
its rules on the ground and in liquid
It walks slowly, so it is a poor way to cross terrain on foot. Touch any liquid and it vanishes outright, and it will not come back until you are clear of it, exactly like the UFO from the Cosmic Car Key. If you already have something that lets you walk on water, the bee inherits that and skims the surface instead.
when to use it and what replaces it
Getting this changes the whole pre-hardmode stretch. Sustained vertical dodging arrives long before wings do, and a featherfall potion running alongside it covers most of what early wings would have given you. The Shrimpy Truffle is the eventual straight upgrade, but that is a long way off, so the goggles stay useful for a large part of a run. Small detail worth watching for: the bee's own flight goggles sit up on its forehead while it walks and drop over its eyes as it takes off.