As of today, Sunday, May 18, 2025, the total number of flight cancellations worldwide is not explicitly stated in the available search results. However, FlightAware reports a total of 20,238 flight delays today, which often correlate with cancellations, but the exact number of cancellations today is not specified

. Other sources provide lists of recent cancellations on specific dates in May but do not aggregate today's total cancellations

. For the most accurate and up-to-date number of flight cancellations today, checking a live flight tracking service like FlightAware's cancellation page or Flightradar24's airport disruption map would be recommended, as these platforms update cancellation statistics in real time