The enormous impact of Delta's system outage was apparent on flight radar as a busy day in the skies came to a virtual standstill.
Flightradar24, a Stockholm, Sweden-based company that tracks the 14,000 or so flights in the air at any given moment, showed what the Delta outage looked like over the United States Monday morning.
As Delta canceled or delayed more flights, the airline appeared to have no planes in the sky around 8:15 a.m. EST Monday morning, Petchenik, spokesman for Flightradar24, told NBC News.
"What we see with Delta's flight activity is obviously covering the United States and a lot going between Europe and North America and a lot between North America and East Asia," Pechenik said. "What we have seen over the past few days is basically a big hole in the sky, as far as Delta is concerned."
As the airline tries to reset after the outage, another 530 flights were canceled by Tuesday afternoon.