Delta Air Lines has seen its share price fall by nearly nine per cent after issuing a profit warning for the final three months of 2018.

The leading United States-based carrier warned investors its unit revenues for the last three months of the year likely rose by three per cent.

This was down from a previous forecast of 3.5 per cent.

The Atlanta-based carrier added yield growth from last-minute bookings “was more modest than anticipated” in December.

The release saw shares fall 8.94 per cent to US$45.61 at close yesterday.

It was the steepest percentage decline in more than six years.

Other US-based carriers followed Delta down, with American Airlines shedding more than seven per cent of its value, recovering slightly after hitting its lowest price since July 2016.

United Airlines lost five per cent, while Southwest Airlines ended the day more than three per cent lower.

The more cautious guidance from Delta came after the carrier warned earlier in December that it expected a “slight deceleration in global GDP” in 2019, potentially threatening profits and travel demand.