A new drone which flies almost silently without wings or propellers has raised questions about how many supposed UFO sightings might actually be man-made craft. The Silent Ventus drone, made by Florida-based start-up Undefined Technologies, uses ion propulsion, with electrodes ionizing the air to generate thrust, and flies incredibly quietly. The hi-tech drones may possibly explain sightings such as the famous'Tic Tac' drone sighting, where pilots spotted a craft resembling the breath mint performing impossible maneuvers during a training mission with the USS Nimitz off the Southern California coast in 2004. Undefined Technologies' claim that its ion-propelled eVTOL drone generates 150% more thrust than rivals (Undefined Technologies) The company hopes to achieve a 15-minute flight this year and believes the drone could be used for'last mile' deliveries (Undefined Technologies) Undefined Technologies' claim that its ion-propelled eVTOL drone generates 150 percent more thrust than rivals. The company hopes to demonstrate a 15-minute flight with noise levels below 70dB this year - ion drives are widely used in satellites and spacecraft, but less common on Earth.

Drones are pretty nifty devices, but the prices for the best ones can often feel as high as the altitudes the drones can reach. Fortunately, B&H currently has a one-day sale on the DJI Phantom 4 Advanced Quadcopter that lets you pick up the device for $370 off the regular price of $1,199. All total, you'll be paying just $829 as B&H is offering free shipping. The quadcopter flies at around 44 miles per hour and can stay up in the air for around 30 minutes. It also comes with five sensors for avoiding obstacles, and its 20MP camera can capture 4K video with a range of 4.35 miles.