Low-cost airline Norwegian has intensified its battle with British Airways in the long-haul market.
The Scandinavian carrier is going head-to-head with BA by launching flights between London Gatwick and Tampa, Florida.
Norwegian announced it will operate twice-weekly flights from October 31, whereas BA has a daily service.
The airlines are already the sole carriers providing flights from Gatwick to New York, Buenos Aires and Oakland.
Test bookings by the Press Association for three return flights to Tampa in October and November on hand-baggage-only fares found that passengers could book with Norwegian for £330, compared with between £457 and £547 with BA.
The BA fares include food and drink, while Norwegian customers travelling on the cheapest tickets must pay extra if they want any refreshments.
Norwegian is also increasing the frequency of its Buenos Aires flights from four per week to a daily service "in response to strong demand",
Norwegian chief commercial officer Thomas Ramdahl said: "Norwegian continues to offer customers increased choice, flexibility and value throughout winter 2018 and we are pleased to welcome Tampa, Florida, as a new destination to our network.
"Our modern fleet of aircraft allow customers, whether travelling for work or leisure, to enjoy their trip from the moment they step on board thanks to our award-winning state-of-the-art entertainment system, comfortable and spacious cabin and friendly cabin crew."
BA's parent company IAG acquired a 4.6% share in Norwegian in April and has subsequently made two takeover offers, which were rejected.
IAG said it was "considering its options", while Norwegian insisted it "remains fully committed to delivering on its stated strategy".
Norwegian has shaken up the long-haul market by offering flights at knockdown prices.
Some of its most popular deals have included £99 flights from Edinburgh and Dublin to New York.
Norwegian's losses before interest and taxes deepened by 31% year-on-year in the first three months of the year, reaching 2.2 billion kroner (£199 million).
Revenues increased by a third over the period, to 7 billion kroner (£632 million).