The American Federal Aviation Administration (FAA) has lifted its ground stop for all U.S. flights but the Ottawa International Airport says some delays may continue. The FAA issued the ground stop on Friday afternoon after a “communication issue impacting all U.S. Air Route Traffic Control Centers,” Secretary Sean Duffy said in a statement on social media. The FAA lifted the ground stop Friday evening, after approximately 5 hours. More than 2,000 flights were cancelled as a result of the grounding. In a Friday evening post on the social media site X, the Ottawa Airport advised passengers that delays may continue even after the ground stop was lifted. “Passengers should continue to check their flight status with their airlines, as some delays may continue while operations return to normal,” the Ottawa Airport said. Of the 36 flights scheduled to arrive at YOW between 12 a.m. and 3 p.m. on Saturday, seven were cancelled. Of the 45 flights scheduled to leave YOW before 3 p.m. on Saturday, six were cancelled. Several arriving and departing flights at Ottawa International Airport have also been delayed. Early Friday evening when the ground stop was still in effect, the Ottawa Airport said all flights to and from the U.S. were impacted “until further notice.” There were two flights scheduled to depart from YOW destined for the U.S. on Friday evening, one to Boston and one to Chicago. There were flights scheduled to arrive in Ottawa on Friday evening from Chicago, Washington, Newark, Fort Myers and Fort Lauderdale. “Please check with your airline before travelling to the airport. We will update information as it becomes available,” the airport said. In statement to CTV News, a spokesperson for the Ottawa Airport said two flights turned back to the airport after departing. While no flights had been diverted to YOW as of approximately 6:30 p.m. on Friday, the spokesperson says the airport is preparing for diversions. NAV Canada implements traffic management In a post on social media, NAV Canada said it is implementing traffic management measures at Toronto Pearson, Montreal-Trudeau, Calgary and Vancouver to “safely manage traffic volumes.” “Travellers should expected delays and check with their airline. Our systems are operating normally,” NAV Canada said. As of 6:55 p.m. on Friday, the following Ottawa flights had been cancelled: For additional information on flight arrivals and departures at the Ottawa International Airport, visit yow.ca/flights.