Austrian Airlines flight OS-121 had to return and make an emergency landing in Vienna, Austria, on November 11th.
The Airbus A321-100 plane took off for Frankfurt, Germany, but had to return shortly afterwards after the crew failed to retract the landing gear.
The plane landed safely. All passengers and crew members remained unharmed.

Pakistan International Airlines flight PK-898 had to divert and make an emergency landing in Karachi, Pakistan, on December 19th.
UtAir flight UT-456 made an emergency landing in Khanty-Mansiysk, Russia, on December 27th.
Air Transat flight TS-423 had to return and make an emergency landing at Gatwick Airport, United Kingdom, on June 10th.
Cathay Dragon flight KA-318 made an emergency landing in Hong Kong, China, on June 13th.
IndiGo flight 6E 293 made an emergency landing in Port Blair, India, on November 20th.