The gap between full-service airlines and budget carriers is increasingly disappearing, according to a new report. Legacy US airlines like American Airlines, Delta and United - plus the likes of British Airways and Air France in Europe - once offered perks such as free seat selection, checked baggage, and complimentary hot meals.

Today, these services are no longer guaranteed, even on so-called full-service carriers. This shift makes the experience on legacy airlines increasingly similar to that of newer budget carriers like Spirit and Frontier, a new report by The Telegraph says.

For instance, almost all North American airlines now exclude checked baggage from basic economy tickets. United has now gone a step further. It has a basic economy fare that only includes a carry-on bag small enough to fit under the seat in front of you. It means passengers have to pay more to take a small cabin-sized suitcase.

In January, Air Canada copied United and rolled out the same rule for its flights within North America and the Caribbean. There are fears Delta and American will follow suit. Additionally, Air Canada is reportedly considering new charges for seat selection Air Canada said they made the change to 'stay competitive with changing market forces in the country.'

Travel expert Gilbert Ott says full-service airlines have now gone 'a step too far' by slashing their included services. 'By removing full-sized carry-on as a full-service airline, you're pitching yourself squarely against the very bottom of the market, which forces you to compete squarely on price and almost price alone,' Ott, who runs the aviation blog God Save the Points told The Telegraph. 'Full-service airlines may not make as much margin from serving the lowest-paying passengers as a true low-cost carrier which has honed this craft over time.'

British Airways now charges extra for checked luggage and seat selection for those travelling on economy basic tickets. Indeed, the majority of 'full service' airlines now no longer includes hold luggage or seat selection for their cheapest tickets, a Telegraph review of 90 major airlines found.

Legacy airlines have also pared back their food and drink offerings in recent years. Air France and British Airway's scrapped their complimentary meals for select short-haul flights. Airlines including KLM, Lufthansa, Swiss, and Finnair have also removed their complimentary food and drink options.

There are however a few 'full-service' airlines that still provide economy passengers something akin to their title. These include Singapore Airlines, Emirates and Qatar Airways.

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