Friday's additional flights will bring Reagan National up to about 250 daily flights -- roughly one-third of the flight load it carried before September 11.

CNN: More flights to depart from Reagan National

On-board, in addition to the flight crew, there was a load master - who had responsibility for ensuring the animals were safe and secure - two attendants and a veterinarian to monitor the animals during the flight.

BBC: Who, What, Why: How do you fly a panda 5,000 miles?

For every route, airlines load a dozen or more different fares into reservation systems and then pick which one applies to a specific flight at a specific time, usually based on how well that flight is selling and what the airline expects in demand for seats, including demand from business travelers who book later.

WSJ: Finding the Best Fares to Europe