MINNEAPOLIS —  Northwest Airlines says it's investigating after the nose cone on one of its planes was damaged during flight.

The plane had been scheduled to fly to Minneapolis from Tampa, Florida. But that flight was delayed after the plane was damaged sometime during a flight between Detroit and Tampa.

Retired Northwest pilot Richard Duxbury says the plane was likely hit by something, possibly a bird. He says bird strikes can be a significant safety issue.

The airline hasn't confirmed that a bird hit the plane. In a statement, Northwest says none of the passengers or crew members were hurt in the incident.