Shrinking rents and consistently strong profits have propelled the Ottawa Macdonald-Cartier International Airport Authority's senior secured debt rating from A1 to Aa3, said John Weerdenburg, the authority's vice-president and chief financial officer.

"It's just our strong financial system," he said, adding the rating has never changed in the airport's history. "Our rent is going down, so we have a lot more flexibility in terms of the decisions we need to make in terms of capital improvements . . . You've always got this balance between affordability and service."

Moody's Investors Service's decision to improve the secured debt rating will lower interest rates and improve the overall value of the bond for current investors in the airport.

The airport is in the midst of a multi-year expansion that saw the old terminal fall, a new terminal spring up, additional gates built and an expanded welcome area for its rapidly increasing numbers of passengers.

Rising gas prices, a new fuel surcharge and increased ticket prices are still not slowing the number of passengers down, as there was a nine-per-cent quarter-over-quarter increase in the second quarter of 2008, Mr. Weerdenberg said.

Direct flights is another business model the airport has been pushing to move away from the traditional routes going through Toronto.

"That new Frankfurt (direct) flight has been full since the beginning of June," Mr. Weerdenburg said. "It hasn't scavenged any passengers from our flights to London Heathrow. So that's been great news."

Annual revenues at the airport are also increasing as of 2007, jumping from $75.8 million to $84.7 million in one year.

The airport will pay about $10 million in rent to Transport Canada in 2008, a number that is expected to almost halve to $5.9 million in 2012.

The rent formula changed in 2005, gradually decreasing Ottawa's rent, as Transport Canada standardized rent guidelines at all Canadian airports.