Budget airlines don't really sell flights any more — they sell flights cheap and make the margin back on bags, seats, and priority. A £20 fare becomes £90 by the time you've added a cabin case and a seat. The single biggest travel saving available to a British traveller is learning to go hand-luggage-only, and for a week's trip it's far more achievable than people think.

Here's the kit and the method.

Know the free allowance exactly

The free "personal item" on Ryanair, Wizz, and easyJet is small and strictly enforced:

  • Roughly 40 × 20 × 25 cm — fits under the seat in front, no overhead locker.
  • A bigger cabin bag (55 × 40 × 20 cm) in the overhead locker costs extra — Ryanair's Priority (~£8–£14), easyJet's large cabin bag fee, etc.

The whole game is packing a week into the free under-seat allowance, or judging when the small priority upgrade is still cheaper than a checked bag.

The bag that does it

  • A 35–40 litre backpack sized to the personal-item limit is the sweet spot — soft-sided so it squashes to fit, structured enough to hold a week.
  • Brands like Cabin Zero, Osprey Daylite, and Decathlon's own range make limit-sized bags cheaply. You don't need an expensive one.
  • Soft over hard — a soft bag flexes into the sizer; a rigid case that's 1cm over gets charged at the gate.

The packing method

A week fits the free allowance if you pack like this:

  • Roll, don't fold — saves space and creases less.
  • Packing cubes — compress clothes and keep the bag sized.
  • Wear the bulk — travel in your jacket, jeans, and heaviest shoes; they don't count against the bag.
  • Capsule wardrobe — a colour scheme where everything mixes, so 5 items make 10 outfits. Re-wear; nobody's counting.
  • Toiletries: solids dodge the liquid rules entirely — bar shampoo, solid deodorant, toothpaste tabs. Otherwise the 100ml-in-a-clear-bag rule still applies (even where scanners are upgraded, pack as if it doesn't).

The fee traps to avoid

  • Don't pay for a seat — if you don't pick one, you're allocated one free. Travelling solo, take the random seat.
  • Check in online and download the boarding pass — airport check-in and printed-pass fees are pure penalty.
  • Weigh nothing, measure everything — cabin bags are sized, not weighed, on most budget carriers. It's the dimensions that catch people.
  • Don't get talked into "priority" unless you genuinely need the bigger bag — the under-seat bag boards fine without it.

The honest maths

A return budget flight with a cabin bag and a chosen seat can carry £60–£90 of fees on top of the fare. Hand-luggage-only, online check-in, random seat: £0. For a week in Europe, the saving frequently exceeds the cost of the flight itself.

Packing light is the rare frugal habit that also makes the trip better — no carousel wait, no lost bag, and you can walk straight out of the airport onto the train.