LONDON — The number of cancellations is decreasing but Delta Air Lines still expects to ground at least 90 more flights globally before operations return to normal later today. Other estimates put the number as high as 150.

Since Monday Delta has cancelled over 1,700 flights. A power outage at its base in Atlanta affected its global computer systems.

“We will have a small number of cancellations [Wednesday] morning as our operation restarts, so we continue to ask our customers to check their travel plans and flight status,” said Dave Holtz, Senior Vice-President for Operations and Customer Centre.

On Delta’s website, the airline advises “if your flight is cancelled or significantly delayed, you are entitled to a refund. Even if your flight is not cancelled, you may make a one-time change to your ticket without fee if you are scheduled to travel … on Delta, Delta Connection, or Delta-coded flights.” The updated policy now applies to all Delta flights with impacted travel dates Aug. 8 – 10. Tickets must be reissued on or before Aug. 21 and rebooked travel must begin no later than Aug. 21.