Thing is nowadays, with UAS/UAV , drone tech, and easy to buy R/C stuff plus quadcopters drones at Amazon and Mens Gift SHops (before xmas seasons selling calendars, R/C helicopters, cars) ...its not that difficult to create any unusual flying object tbh. Hell on youtube a couple of pranksters in US converted a toy spider into an R/C thing and knocked on peeps doors then the spider UAS lept into the air onto the startled resident.
Go back 15 years, went to the very last Maxpower Live (lots of nice models lol sadly cannot find my images from that sunday lol!)...me and mate bought one of these toy flying suacer with red flashing light from one of the stands selling gadgets. It was powered by a coil and was around size of a football. Anyhow powered it up then tested in the garden late at night lol....it hovered just around the garden sheds height...
Also around that time, does anyone remember a Channel 4 or 5 documentary showing a bunch of engineers down in Surrey constructing a very large flying saucer. Said saucer was fitted with red light and flying it around the countryside spoofing peeps. As the radio range was limited so several of the team stood mile or so apart. Just for legality they asked CAA to give them an exemption. And the result was as expected lots of calls to the cops
Problem is in Syria, the big bad guys are using drones as weapons...so its not incoceivable for a group to cause havoc in the airspace especially around an AAF/ AFB/MCAS/NAS by flying an unusual shaped UAS just to put the wind up the authorities. Case in point with LGW drone incident before xmas (I was one of the 150,000 odd passengers stuck there for few extra days).
Cheers