The airline has not yet been confirmed thought it is suspected it may involve a domestic flight.
The only scheduled departure between 6am and 9am was for a daily TAP flight from Faro to Lisbon which was set to depart at 6.05am, but according to the ANA aiport website the status of flight TP1900 is "closed" and had not yet made the 30-minute flight to the capital as of 7.45am.