On July 17, 2026, more than 10,700 flights across the United States were delayed due to hazardous air quality caused by smoke from over 900 active wildfires burning in Canada. The delays affected airports in the U.S. Midwest, Great Lakes region, and East Coast, including major hubs such as Detroit Metropolitan Airport, Chicago O’Hare, and Philadelphia International Airport.
Philadelphia International Airport recorded 365 delays and 12 cancellations on July 16 and continued to experience more than 200 delays on July 17, prompting the Federal Aviation Administration (FAA) to impose a ground delay program. Other affected airports include Toronto Pearson, Buffalo,
Syracuse, Rochester, Duluth, Minneapolis-St. Paul, Milwaukee, Green Bay, Grand Rapids, and Madison.
Airline Travel Advisories and Rebooking Policies
United Airlines issued an air quality travel advisory covering 17 airports in the U.S. and Canada, including Detroit and Toronto Pearson. The airline allowed passengers holding tickets purchased by July 16 to rebook their July 16-20 flights without fees or fare differences, provided travel remains between the same city pairs and in the same cabin. The United Airlines rebooking window expires on July 20.
Delta Air Lines applied a Midwest Air Quality Advisory for flights between July 16 and 18 operating from airports in Michigan and Wisconsin such
as Detroit and Green Bay. Delta permitted no-fee rebooking on same-cabin flights through July 21.
American Airlines experienced delays on 42% of its flights on July 17 — more than double its 2026 average of about 20%. It issued waivers covering 29 airports with a no-cost change deadline on July 18; unused ticket value can still be applied toward future travel within one year if no rebooking was made.
Air Quality Impact and Forecast
Air quality indexed by fine particulate matter (PM2.5) reached hazardous levels impacting over 100 million people across 18 U.S. states. Northern Minnesota and Detroit recorded exceptionally high Air Quality Index (AQI)
readings near 600 on July 16–17, far exceeding the Environmental Protection Agency’s (EPA) hazardous threshold.
On the morning of July 19, Chicago’s AQI measured approximately 153, ranking it the world’s second worst major city for air quality. The National Weather Service (NWS) forecasted unhealthy air persisting in the Great Lakes region, including Chicago, Detroit, and parts of the Northeast due to a third wave of wildfire smoke.
The EPA recommended limiting outdoor physical activity when AQI exceeds 150 and avoiding outdoor exertion above 200. N95 or KN95 masks were advised as the effective means to filter harmful PM2.5 particles. The
FIFA World Cup Final scheduled for July 20 at MetLife Stadium in East Rutherford, New Jersey, is expected to proceed despite the smoke conditions.
Political and Legal Responses to the Wildfire Smoke Crisis
On July 17, U.S. President Donald Trump announced via social media his intention to increase tariffs on Canada, blaming Canadian wildfire management for the smoke damage. However, a February 2026 Supreme Court ruling invalidated presidential authority under the International Emergency Economic Powers Act to impose tariffs, casting doubt on any such action.
Current tariffs under Section 122 of the Trade Act, including a 10% global tariff, are set to expire on July 24. The U.S. Trade
Representative, Jamieson Greer, declined to renew the Canada-United States-Mexico Agreement (CUSMA) in its current form as of July 1, adding uncertainty to the trade relationship.
Canada’s Prime Minister Mark Carney emphasized international responsibility for climate change, stating it is “the responsibility of all countries, including the United States.” Emergency Management Minister Eleanor Olszewski noted Canada has invested $12 billion in forest sustainability and fire prevention since 2020. Ontario Premier Doug Ford challenged the U.S. to lift softwood lumber tariffs exceeding 45%, including an extra 10% imposed in October 2025, as a more constructive approach.
Wildfires Linked to Climate Change and U.S.-Canada Cooperation
Scientists attribute the wildfires causing cross-border
smoke to a record-breaking heat wave, not forestry mismanagement. On July 13, temperatures in Ontario were 25.2°F above average, according to Climate Central meteorologist Shel Winkley, who said such heat would be “virtually impossible” without climate change.
The 2026 Canadian wildfire season is at 134% of the 10-year average by mid-July, while U.S. burned acreage stands 31% above its decade average. The U.S. and Canada maintain bilateral wildfire cooperation agreements since 1982, reaffirmed in 2025 to facilitate joint fire prevention and response efforts.
Meanwhile, the Trump administration has proposed closing several wildfire smoke research facilities including the Pacific Wildland Fire
Sciences Lab in Seattle, which provides critical data for smoke tracking and management.
Travel Recommendations and Airspace Status
Travelers using U.S. airports affected by the smoke are advised to consult the FAA’s National Airspace System status page and verify flight status directly with airlines. Extra connection time is recommended at major hubs such as Philadelphia, Chicago O’Hare, and Detroit due to prolonged delays.
The smoke-induced visibility reduction differs from typical weather delays and limits air traffic controller rerouting options. As such, travel disruptions are expected to continue while air quality remains hazardous.
