The National Hockey League regular season has yet to begin, but elbows are flying in an aviation scrap between the U.S. and Canada that threatens to disrupt air-charter arrangements made by many NHL teams. Air Canada last week sued U.S. Transportation Secretary Ray LaHood, seeking to block his enforcement of an Aug. 11 Transportation Department order that Air Canada to cancel its season-long sports charter contracts. Air Canada’s Jetz charter service currently has contracts with the six Canada-based NHL squads and the Toronto Raptors basketball team. The ruling “is wreaking havoc on the hockey season,” said Air Canada, a unit of ACE Aviation Holdings Inc., in its lawsuit. “The urgency of this matter cannot be minimized.” Air Canada claimed the U.S. position has cost it contracts with three U.S. NHL teams this season, including the Boston Bruins. The Bruins declined to comment. At issue is whether Air Canada is allowed to fly Canadian sports teams between U.S. destinations without first returning to Canada. By law and treaty, foreign airlines can’t pick up passengers when flying between U.S. cities — nor can U.S. airlines in most foreign nations, including Canada. However, the DOT for years has allowed Air Canada to fly sports teams on back-to-back U.S. flights if the teams ultimately would return to Canada. Similarly, U.S. airlines ferrying American teams have been allowed to fly within Canada. But the Air Line Pilots Association union, two U.S. aviation trade groups and a U.S. charter carrier began calling for a penalty last year because Air Canada won DOT-approved contracts to fly two American sports teams, the NHL’s Bruins and the Milwaukee Bucks of the National Basketball Association. The pilots want to assure that U.S. flights are operated by U.S. pilots. In an order to Air Canada’s Washington lawyer, the DOT said the agency found the airline last year carried individuals on Bruins and Bucks charters who were transported within the U.S. and never carried across the border during the season, contrary to the DOT’s agreement with the airline. Canada’s Minister of Transport, John Baird, said in a letter to Mr. LaHood demanding the DOT retract its decision. This Canadian Transportation Agency retaliated by banning flights by U.S. carriers that require multiple stops within Canada. Miami Air International Inc., a U.S. charter carrier that has contracts with 10 NHL teams this season, had to arrange for a Canadian charter to make intra-Canada flights last weekend for the Florida Panthers, rather than carry the NHL team itself, said Ross Fischer, chief executive of Miami Air. Miami Air also had to amend its travel plans last weekend for a major-league baseball client, the Toronto Blue Jays, Mr. Fischer said. Instead of flying the team to Windsor, Ontario, from Toronto, as the team requested, the flight went to Detroit. “We’re scrambling,” Mr. Fischer said. But the situation is worse for Canadian teams because they have more back-to-back games in the U.S., where there are 24 NHL teams. Canadian teams could be forced to return home between each U.S. game, which would be expensive. Bill Daly, deputy commissioner of the NHL, said the league is “concerned with these new interpretations, especially on the eve of the new season when our teams have all made their travel arrangements already.” Air Canada said it hoped a solution could be reached. In its suit, the airline said it has a permit to operate charter service between any points in Canada and the U.S. Because of the treaty between the U.S. and Canada, Air Canada said it can make an unlimited number of U.S. stopovers, which allows the airline to offer charters for sports teams whose schedules require play in both countries. The contract and season itinerary is treated as a single journey with multiple stopovers, the airline said. A hearing on Air Canada’s complaint, filed in U.S. District Court in Washington, D.C., is scheduled for Tuesday. A DOT spokesman declined to comment, as did a spokesman for Transport Canada. The preseason was to begin Monday; the regular season Oct. 1.