New plane seat designs may make it harder for travellers to pack carry-on only bags

If you're the type of traveller who prides themselves on taking holidays with nothing but a carry-on bag, your days of gloating could soon be over.New airplane cabin designs, which aim to maximise space, could see a reduction in the amount of space underneath each seat.With a focus on thinner seats, so more can be packed into a cabin, this means there is less room to stow both your bags and your legs comfortably.READ MORE: Here are 12 things to do in Melbourne that cost less than $12Of course, the overhead bins are still an option. But some budget airlines, particularly those in Europe, only allow travellers to fly with a bag that fits under the seat unless they want to pay an extra fee.Thankfully, Aussie airlines allow us to bring carry-on suitcases aboard without needing to pay an extra charge.But if you're planning to take a trip on budget airlines in Europe or Asia, you might be hit with different rules. Irish carrier Ryan Air only allow you to bring on one small personal bag, such as a handbag or laptop bag (40x20x25cm), which must fit under the seat in front of you. For anything bigger, you'll have to pay a fee.Other low-cost carriers like Wizz Air in Europe, and Frontier, Spirit, and United in the USA have similar policies.READ MORE: From ruin bars to thermal baths, here are the must-do things on your first visit to BudapestExpert Christopher Elliott wrote in a USA Today article: "When an airline announces a new cabin interior, it often moves to thinner seats, which allow it to add more capacity."Installing extra rows of seats usually means subtracting legroom."He said that on a recent short flight in the USA, there wasn't enough leg room for him to sit comfortably with his legs facing forward. "I had to lean sideways for the brief trip."READ MORE: Eating in Paris: 7 must-try bites (and where best to enjoy them)Anyone with long legs knows that some budget Aussie airlines have similar space issues, particularly on planes flying short trips that are under a few hours long.One airplane designer thinks we should do away with overhead bins altogether, and forget the idea of carry-on luggage."I'd say we're at a breaking point. We've hit as big as we can go," says David Young, a plane cabin designer."Maybe we don't need carry-ons at all. Someone needs to step out and say, 'We're not doing this anymore. This isn't the right experience for air travel.'"