India, Aug. 7 -- United Airlines experienced a massive system outage on Wednesday, resulting in several flight halts and a FAA ground stop across several airports. The airline said that it is 'expecting additional flight delays this evening as we work through this issue'. Now, theories about a system hack have emerged.

"Due to a technology issue, we are holding United mainline flights at their departure airports," the airline further added.

Ground stops were in place at airports including Denver, Houston, New Jersey, San Francisco, and Chicago, according to the US Federal Aviation Administration (FAA). This comes days after Alaska Air temporarily grounded its entire fleet due to a data center equipment failure that affected several of t...