The world's most luxurious flight experiences - from an onboard spa to a decadent cocktail lounge in the sky

From en suite bathrooms to separate living spaces and dips in thermal jacuzzi pools, for some carriers, the sky is quite literally the limit when it comes to onboard luxury.As such, AirAdvisor has analysed some of the most extraordinary experiences currently available to passengers on commercial airlines, and rated each one out of 100.Considering factors such as extravagance, rarity, privacy and exclusivity, scarcity of access, and how far the experience extends beyond the seat itself, the flight and baggage compensation company has highlighted the top ten carriers offering the ultimate luxuries in the sky.Only one British carrier makes the cut – Virgin Atlantic – while Emirates managed to impress twice. Here are the ten most opulent airline experiences money can buy.1. Etihad Airways, The Residence The Residence, offered by Etihad Airways, is a private apartment in the skyComparable to a private apartment in the sky, The Residence can be found on Etihad Airways' A380.Travellers are treated to a private bedroom with a double bed, an en suite shower and a living room.But this top-tier service begins before passengers even step onto the plane – with home or hotel check-in included, as well as chauffeur transfers and a personalised airport welcome. Scoring a near-perfect rating of 98 out of 100, there's enough space for up to two guests and Etihad describes it as 'an experience that must be lived to be believed'.While the full price is route-dependent, fares are usually between $11,000 and $25,000, one-way. 2. Emirates, A380 Shower Spa First class passengers flying with Emirates can indulge in the A380's shower spa Forget waiting until you get to your hotel to splurge in the spa, Emirates offers one at 40,000ft. First-class passengers on the airline's A380 have access to the dedicated shower room.It boasts everything they might need to refresh during a flight, including a vanity area, changing space as well as heated flooring. Access to this pamper palace comes with a first-class ticket on the Emirates Airbus A380, for which fares start from approximately $15,000. 3. SWISS, First Grand Suite SWISS offers a First Grand Suite which converts two adjoining suites into a secluded loftThis year, Swiss International Air Lines (SWISS) launched its First Grand Suite on long-haul routes. It allows two adjoining first-class suites, including the aisle, to be combined into a single extensive and exclusively secluded loft space.While prices for these new suites are not advertised at a fixed rate, they are thought to cost around three times a regular first-class ticket price, which start from approximately £6,400 for a round-trip.4. Air France, La PremièreOver at Paris-Charles de Gaulle, Air France passengers can indulge in the carrier's La Première private suites. With 45m² of secluded space to enjoy, the suite includes a living and dining area, a bedroom with a double bed and a bathroom.There is even an outdoor patio perfect for getting some fresh air before the flight. Guests also have access to the Sisley spa and the La Première lounge.Depending on both route and season, these tickets cost between $10,000 and $20,000. 5. Singapore Airlines, Suites The A380 suites offered by Singapore Airlines feature a separate full-flat bed and a leather chairSingapore Airlines’ A380 Suites offer a private space to relax and rest during your journey. Each space includes a separate full-flat bed and a leather chair. If travelling as a pair, selected adjoining suites can be combined to create a double bed. 'Your private space. On your terms,' the airline says. Rooms include a 32-inch HD touchscreen monitor as well as an entertainment system and free Wi-Fi. While the airline doesn't typically disclose the prices for these suites publicly, the experience is thought to cost between £7,900 and £23,730.6. Lufthansa, Allegris Suite Plus Lufthansa's Allegris Suite Plus has two extra-wide seats which convert into a double bedBoasting similar features to Singapore Airlines, passengers can also indulge in Lufthansa's Allegris First Class Suite Plus. The private double suite has two extra-wide seats, which convert into a double bed.Lufthansa promises passengers: 'plenty of space, maximum privacy, and special moments.'Prices start from around £14,500 return. 7. Japan Airlines, A350-1000 FirstLooking for plenty of room and exclusivity? Japan Airlines offers its 'most spacious and relaxing seats ever' with its A350-1000 First Class suite.The airline has six seats in a 1-1-1 configuration to maximise the area and each suite offers a bed up to 123 cm wide and 203 cm long.Passengers even have a personal wardrobe, minibar and a 43-inch personal screen.Depending on the route and seasonal demand, tickets cost from an average of £11,000. 8. Emirates, A380 Onboard Lounge Passengers can sip cocktails and meet other travellers in Emirates' A380 onboard loungeBusiness class passengers on Emirates' A380 can make the most of its new onboard lounge. The cocktail bar space offers the chance to sip drinks and socialise in a luxurious area that hardly even looks like a plane. 'Network as you delve into delicious canapés,' the airline says. Emirates business rates start from approximately £2,585, depending on the route and the season. 9. Qatar Airways, Al Safwa First Lounge The Al Safwa First Lounge is a luxurious space offered by Qatar Airways in Hamad International AirportAdorned with 'a blend of elegance and refinement with opulent features and captivating installations', Qatar Airways' Al Safwa First Lounge offers a luxurious start to any journey, before you've even boarded the plane. Located in Hamad International Airport, Doha, guests can access the Qspa, which offers nine treatment rooms and a thermal jacuzzi.Qatar Airways says: 'Our focus is on perfecting every moment with meticulous detail so that you can enjoy a seamless journey from the moment you arrive until we bid farewell.'Access to the lounge is available for a paid upgrade fee of around £120, or is offered as a complimentary service to eligible passengers. 10. Virgin Atlantic, Retreat Suite Virgin Atlantic's Retreat Suite has enough room for up to four business class passengersThe only British airline to make the list, Virgin Atlantic impresses with its Retreat Suite offering. The space offers up to four business class passengers the chance to dine, work or socialise together. It can be found onboard selected A330neo aircraft.The Retreat Suite typically costs an additional £200-300 per seat, in addition to a standard Upper Class ticket.