Aircraft interiors have long been a battleground for luring passengers with plusher cabins, bigger seats and fancier food. The fight for a new generation of travelers is intensifying as a dearth of upcoming new jetliner models forces airlines to get creative.

Among developments this year, Qatar Airways revealed a business berth which can be swiveled to form a meeting area for four, or even a double bed. Dubai-based Emirates is giving its flying bars a saloon-style redo with table seating targeted at passengers who prefer to linger over their Bloody Mary. Its A380s already offer airborne showers, while those operated by Etihad Airways of Abu Dhabi boast a three-room suite with personal butler. At the same time, Airbus Group says it may shrink the double-decker's so-called grand staircase to add capacity and improve the model's mass-market appeal.

The next generation of gizmos, on show at the 2017 Aircraft Interiors Expo in Hamburg starting Tuesday, includes innovations aimed at boosting seat density, automating in-flight service (watch out cabin crew!) and keeping passengers entertained. Alongside the more practical advances are others that may not ever see the light of day. Bloomberg picks out five innovations worth a look.

Cyborg Server

Tired of losing the beverage-cart lottery? Paris-based Altran has invented a robotic waiter that takes your drink and snack order in advance and rolls it up to your row. The self-driving trolley also collects garbage at the end of the flight, which leaves more time for human attendants to focus on important issues like safety. And fashion violations. Alas, the robot lacks arms, so the job of passing hot coffee to window-seat passengers will be outsourced to the lucky aisle-seat occupants.

Germ Killer

Using technology that's already in action to disinfect hospitals and municipal water supplies, the GermFalcon will zap ultraviolet light across the cabin to sanitize armrests, tray tables and even toilets. It looks like a beverage cart with arms and can destroy bacteria and viruses on 54 seats in 1 minute. There's already so much radiation at airports and in planes, who's going to be bothered by a few rays more?

Flying Gourmet

If your steak's overdone you can soon send it back. Deutsche Lufthansa is making flight-safe cookers that fry eggs, toast bread and steam rice at 30,000 feet. Don't worry about your freshly pressed suit smelling like a greasy spoon by the time you land for your meeting: the science-lab look-alike comes with a fume hood. And a lock meant to prevent a skillet full of sizzling sirloin from flying down the aisle during turbulence.

Window Surfing

You've secured the window seat, popped in your earbuds and nestled your travel pillow into place. Now for a relaxing view of, err, stock prices. Vision Systems, based in Lyon, France, wants airlines to turn their windows into pane-shaped infotainment screens that passengers can swipe through to see flight details, order drinks and -- naturally -- buy stuff. If you want to unplug, the screens can be dimmed so you can see the clouds through tinted glass.

Space Maker

Sliding seats are the way of the future. That's what Molon Labe Designs wants you to believe. Its pitch for reconfiguring cabins includes an aisle seat that slides over the middle seat to widen the corridor during boarding. The Denver-based startup also boasts middle seats that are the industry's widest at 21 inches, and positioned farther back and slightly lower than the neighboring spots, creating less scope for armrest battles.