On Oct 31, 2013, a Norwegian Boeing 737-800#LN-DYC en route from Trondheim to Oslo with 130 passengers and 6 crew, was descending towards Oslo and was switched to a different runway. A second Norwegian Boeing 737-800 #LN-NOM en route from Oslo to Trondheim took off. Instructions from ATC became confused, and both planes followed a single instruction, bringing them into proximity.
Flight 741, which was landing, was below Flight 740. Flight 740 got a TCAS (Traffic collision avoidance system) warning and diverged. Accident Investigation Board Norway noted the minimum separation between the two aircraft was down to 0.2nm lateral at 500 feet vertical.
American Airlines flight AA-142 had to divert and make an emergency landing at Shannon Airport, Ireland, on September 9th.
Alaska Airlines flight AS-959 made an emergency landing in Portland, Oregon, on May 13th.
Southwest Airlines had to return and make an emergency landing in Seattle, Washington, on January 1st.