The end of Southwest’s much-loved free checked bags policy could have two unintended consequences. 

The budget airline, which earlier this year revealed plans to impose fees on checked luggage, might now encounter delays in departures due to extended check-in and gate queues.

Customers must now pay $35 for one bag and $45 for the second, after the new policy went in to effect on May 28.

Southwest estimates a 30 percent drop in checked baggage volume and a surge in carry-on as hard-pressed consumers try to evade the fees.

But experts point out two problems. Check-in lines will grow as fliers take time to pay for bags at the airport.

Gate-checking lines will also grow as Southwest planes have limited overhead locker room for carry-on bags, and will be unlikely to meet new demands.

Southwest boasts the lowest cancellation rate among its US competitors so far this year, with an on-time performance exceeding 80 percent, as reported by aviation analytics company Cirium.

Should the airline fail to alleviate the ripple effects of its new policy, passengers could experience a marked decrease in punctual departures as the summer travel rush begins.

Southwest is anticipating a 30 percent increase in its cabin bags after June 1 

Checking passengers’ bags as they board the plane is a time-consuming activity and may cause flight delays as the airline and its passengers get used to the new system.

On the airline’s smallest planes, there tend to be five or six carry-ons that need to be checked, Justin Jones, executive vice president of operations at Southwest, told the Wall Street Journal

But as bag fees go into effect, he predicts this could surge to 25. 

The airline has begun deploying new technology to speed up check-in and gate waiting times. 

This includes an AI ‘Lobby Awareness Tool’ that predicts airport wait times based on flight schedules and passenger-arrival patterns. 

This will help the airline know when to deploy extra employees to help deal with a bottle-neck and minimize delays. 

Another tool is the Baggage Estimation Based on Passengers, or Bebop, which will help to predict how many carry-ons will have to be checked at the gate.  

‘It was a curve ball that we were thrown,’ Jones previously told the Airlines Confidential podcast. ‘We always carry more bags than anyone else out there,’ Jones said. 

The airline has introduced fees for checked luggage after 50 years 

Southwest bosses predict they will now need to take five times more bags at the gate and put them in the hold

Bob Jordan, CEO of Southwest Airlines, previously announced staff cuts 

Indeed, customers have famously taken advantage of Southwest’s generous policy to transport kitchen sinks and toilets across the country. 

‘We’re going to need to do several things,’ but ‘we want to make sure the customer experience is still very high,’ Jones told the podcast.

‘So we’re going to be extremely hesitant to go out and do heavy policing on bag size like some other carriers do.’

However, the policy change ‘will result in more gate checked bags and fees.’  

‘We’re dependent on everything kind of flowing,’ Jones said of Southwest’s business model which relies on keeping aircraft in the skies rather than wasting time on the ground. 

Long-term Jones said the answer will be in the introduction of new planes to Southwest’s fleet with more cabin bag capacity. 

Customers have criticized he new rules. ‘The only reason people put up with no assigned seating was because they could check free bags. This is no better than a bus, now,’ one wrote on Reddit.

The fees are part of Southwest’s efforts to boost its bottom line. 

In February the airline announced plans to cut 15 percent of its corporate workforce in a bid to cut costs.

The layoffs – a first in the airline’s 53-year history –  will slash around about 1,750 jobs.