It was previously not known that she had made the authorities aware she was not feeling well before taking the flight on 13 October.
The Centers for Disease Control and Prevention (CDC) has been forced to track down 132 other passengers who were on the plane at the same time in case they too have been infected.
Federal officials were forced to admit on Thursday that the CDC cleared the nurse to fly, heaping further pressure on an organisation that has been criticised for the speed of its response to the ebola crisis in America.
CDC spokesman David Daigle said 29-year-old Miss Vinson reported that her temperature was below 100.4 degrees and had no symptoms. Ebola sufferers aren’t contagious until they show symptoms.
As a result, the nurse was told she could travel on Frontier Airlines Flight 1143.
The plane’s crew said Miss Vinson did not exhibit any symptoms of ebola during the flight on Monday.
Miss Vinson caught ebola after being one of several nurses to treat a man who came down with the virus and died after travelling to the US from Liberia.
She is the second nurse who treated Thomas Eric Duncan to test positive for ebola after he died in Dallas on 8 October.
The fact that two nurses caught the disease have also raised questions about how ready the US has been to cope with the virus.
More than 4,400 people have died in the western African states of Liberia, Sierra Leone and Guinea in the disease’s worst ever outbreak.
The nurse has been transferred to Emory University Hospital in Atlanta, where two Americans who contracted ebola while working in west Africa were successfully treated and released.
The director of the CDC Dr Tom Frieden had earlier said that Miss Vinson should not have been allowed to travel by plane, but added that “the level of risk to people around her would be extremely low”.
The other infected nurse, 26-year-old Nina Pham, remains in isolation at Texas Health Presbyterian Hospital in Dallas and is said to be in stable condition after receiving a plasma transfusion donated by ebola survivor Dr Kent Brantly.
President Barack Obama has cancelled a scheduled trip to Rhode Island and New York to remain at the White House to monitor the government’s response.
On Tuesday, Mr Obama reiterated that an ebola epidemic in the US was “highly unlikely”, but added that even one case “is too many, and we’ve got to keep on doing everything we can”.