The carrier’s check-in systems and passenger advisory screens were affected during a systems failure on August 8 at a number of terminals.

Delta’s website and smartphone apps were also affected by the issues, which led to thousands of travellers being struck by delays in the UK, Japan, Italy and US.

The carrier revealed the financial impact of the outage in its results for the third quarter to September 30 last week.

“The technology outage and subsequent operational recovery Delta experienced over four days in early August reduced pre-tax income for the quarter by an estimated $150 million,” the airline said.

Net income fell by around 4% to $1.3 billion in the third quarter, which was a slightly better performance than analysts expected.

Its operating revenue of $10.5 billion was 5.6% lower than the same period last year, of which $100 million was due to the outage and $70 million was from prior-year yen hedge gains.

Ed Bastian, Delta’s chief executive, said: “Delta’s resiliency stood out this quarter as we worked through the outage, continued revenue headwinds and volatile fuel prices to produce the industry’s best operational reliability and service for our customers along with solid margins, cash flows and returns for our owners.

“With our focus on building a more sustainable and durable business, we will be taking a cautious approach to 2017 by keeping our capacity in line with the December quarter’s 1% growth level.”

Glen Hauenstein, Delta’s president, added: “While we were encouraged by our unit revenue trends through the September quarter, we have more work ahead of us to achieve our goal of positive unit revenues.

“With further slowing of our capacity growth in the December quarter and additional traction on our revenue management initiatives, we should make progress against that goal and we expect our December quarter unit revenues to decline by 3-5% year-over-year.”

Delta generated $1.8 billion of adjusted operating cash flow and $1.1 billion of free cash flow during the quarter. The company used this to invest $680 million into the business for aircraft purchases and improvements, facilities upgrades and to support maintenance initiatives.

During August’s technical problem Delta offered refunds and $200 travel vouchers for passengers who suffered delays of more than three hours or had their services cancelled, while Bastian apologised to travellers in a video message.