It's not uncommon for tech companies to try to build an outlandish product and then leave it rotting in a drawer. It's entirely possible that Evan Spiegel and chums tried building a drone and found that it wasn't worth the effort.
But then again, it also points to a company that is looking to build products to widen a portfolio that began with Spectacles. Snap will also have to work out a way of turning a better profit on its hardware offerings, since the video-recording glasses don't make a lot of cash.
There's also the fact that Snap conceded in its IPO documents that it is a young company without a lot of experience in building hardware. But hardware is probably a safer bet than trying to innovate the Snapchat app itself -- especially since Facebook quickly copies its innovations.