Feb 25 (Reuters) - A Southwest Airlines ( LUV ) jet was

forced to abort a landing at Chicago Midway on Tuesday after a

business jet entered the runway without authorization, the

Federal Aviation Administration said.

Southwest Flight 2504, a Boeing 737-800 arriving from Omaha,

flew overtop a FlexJet Challenger on the runway and performed a

go-around. The FAA is investigating the incident, which occurred

around 8:50 a.m. CT.