Incorrectly regarded as goofs: Perceived errors regarding insect anatomy are part of the movie's internal logic and suspension of disbelief. (See trivia entry.)
Continuity: At one point all the trees and plants have withered because of a lack of pollination. But when all the bees fly out to help guide in the plane, the tree in front of the hive is sporting big green leaves.
Continuity: The windshield-wipers that Barry and the mosquito are riding on, don't move all the way over to the driver's side of the wind-shield. However; the marks made by the wipers do go all the way over to the driver's side of the wind-shield.
Errors made by characters (possibly deliberate errors by the filmmakers): When Ken confronts Barry in the bathroom, he rolls up a magazine. Barry asks what type of magazine it is, and Ken replies, "Italian Vogue". But it clearly says Paris on the front.
Factual errors: Although a large enough swarm of bees could theoretically generate as much lift as a jet liner, the bees would have experienced "vacuum" forces between themselves and the body of the jet at the speeds depicted, rather than generating lift, like two ping-pong balls being drawn together by blowing a stream of air between them.
Factual errors: The movie depicts bees using pollen from just one kind of flower to pollinate several different plant species. Flowers can only be pollinated with pollen from the same species.
Factual errors: Plants don't wither and die if they are not pollinated, they simply don't develop viable seeds. Although bees do contribute significantly to the pollination process, other animals do the same thing, not to mention that a simple gust of wind can cause pollination. Unpollinated plants will simply bloom again at another time, giving another chance for pollination.
Continuity: When Vanessa has just saved Barry and has him under a glass with Ken's brochure underneath the glass. There is a close up and the word "backwards" can clearly be read although upside down. The shot changes to Vanessa opening the window and letting Barry out. Barry and the glass are now over a photo.
Continuity: At the beginning of the movie, Barry is finishing up getting ready for graduation and flies down the stairs. His bum does not have his stripes - it's solid black. You will notice that Adam has a solid black bum though.
Factual errors: Commercial jet airplanes of that size usually are going faster than 500 miles per hour, and the fastest insect (not the bee) only goes at about 30 miles per hour.
Plot holes: A lightning strike to the airplane disables its systems. Jet airliners, however, are struck by lightning regularly, without trouble. They're designed to withstand it.
Errors made by characters (possibly deliberate errors by the filmmakers): The jet captain wears a co-pilot/first officer insignia.
Errors made by characters (possibly deliberate errors by the filmmakers): Someone claims that the Pasadena parade has the "last flowers in the world." But Barry's lawsuit only affected the USA; bees in other countries are presumably still pollinating flowers as usual.
Errors made by characters (possibly deliberate errors by the filmmakers): It is mentioned that Ken's face puffs up when he's around bees during the beginning. But later when he's interacting with Barry, he shows no signs of any allergic reactions.
Factual errors: The "laws of aviation" from decades ago explained the flight of large objects such as airplanes and birds but failed when applied to really small objects like bees. Modern laws of aviation do explain the flight of bees.