As airline cancellations increase, seats are scarce and the shortage of availability is seeing air fares soar to unprecedented levels.

Following a string of cancellations on Thursday between London and Dublin, almost all flights between the UK and Irish capitals are full for the day on Friday.

The late evening departure from Heathrow on Aer Lingus is selling at £450 for the 290-mile, 75-minute journey.

On Saturday, the lowest fare from Gatwick to Dublin on Ryanair is £239, with the afternoon departure priced at £308.

During the first 11 days of July, high fares are inevitable on British Airways from London Heathrow. BA is is taking one in nine flights out of its schedule this summer. Yesterday, the UK’s busiest airport stipulated 30 last-minute cancellations, around half of them on British Airways.

In order to protect passengers already booked on early July flights in case of further groundings, fares have been pushed to very high levels. Prices have risen to as much as £2.23 per mile for a one-way economy journey.

On all British Airways Heathrow-Rome flights up to 11 July, the lowest economy one-way fare is £666.

From London to Athens, Gatwick flights are affected too. The cheapest ticket on BA is £752, flying from Gatwick. From Heathrow, the fare is £5 more.

On a per-mile basis, Amsterdam is top among international routes, with the lowest fare from Heathrow currently £516 for a journey of 231 miles – a rate of £2.23 per mile.

Heathrow-Manchester (£415, 151 miles, £2.75 per mile) is the most expensive overall and domestically, with the link to Newcastle priced at £463 for a trip 100 miles further (£1.85 per mile).

Flights to southern European beach destinations are reaching levels normally associated with long-haul trips.

On the only Ryanair flight not sold out from London Stansted to Faro in Portugal on 23 July, the late evening departure, a one-way ticket costs £262. Peak day for returning is 3 September, when the corresponding flight is €300 (£256).

On the same day, easyJet’s afternoon flight from Preveza in western Greece to Gatwick is €850 (£726), excluding baggage. A late-night departure is cheaper at €466 (£398).

Flying midweek, on Tuesday 26 July, Ryanair is charging £304 from Liverpool to Alicante on Spain’s Costa Blanca.

Within Europe, city break destinations are rising too. From London to Prague on Sunday 24 July, for example, easyJet is charging £334.

Long-haul fares are also extremely high in July and August. The cheapest Virgin Atlantic return fare between London Heathrow and New York JFK on 23 July for a fortnight is £1,271. This includes only cabin baggage, for which the airline’s allowance is a single bag weighing no more than 10kg.

From Heathrow to Orlando in Florida on the same dates, only three tickets are available at a lowest fare (including baggage) of £1,618 return.

Even on the Canadian budget carrier, Air Transat, transatlantic fares are sky-high: on the same dates (23 July out, 6 August back) just two seats are available from Gatwick to Toronto at a fare of £1,119.

Paul Charles, chief executive of travel consultancy The PC Agency, said: “Airlines are passing on the higher costs they are seeing from their own suppliers, but also increasing prices due to sharply higher fuel costs.

“That’s in addition to the greater demand for seats on the fewer flights operating. Airports may be capping the number of flights, but that’s not helping passengers who are having to fit onto fewer departures.

“All of this at a time when consumers expect better service quality for the higher fares they are paying. It’s a real challenge for the aviation industry and I don’t see it improving hugely in the coming weeks.”

Some relative bargains are still available. Even though schools in Scotland have broken up for the summer holidays, Jet2 still has availability from Glasgow to Alicante on Saturday for £153. Similarly from Manchester to Malaga on Saturday 23 July, the first day of the school holidays for many families in England, Ryanair has two seats left at £122.

Flexible travellers able to go midweek at short notice get the pick of the bargains. From Stansted to Bergerac in southwest France, outbound on Monday 4 July and back on Thursday 7 July, a return ticket on Ryanair is £26.

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