Carol Cork, marketing director of PrivateFly, a global booking service for private jets, said the firm goes out of its way to satisfy customers' needs, and the requests can be extremely unusual.
Often, the unusual request revolves around a special occasion.
For one flight, they had to arrange for a firefighter to be on board because there would be an open flame.
Cork said: "This client wanted to have her 50th birthday cake candles lit on her birthday trip to Florence, so we arranged for a fireman to go along too.
"Luckily it was a large aircraft with seats to spare."
Recently, PrivateFly arranged a Scottish-themed flight for a client's 100th birthday.
The client wanted bespoke tartan seat covers, a fine-dining Scottish menu and a bagpiper at the aircraft steps.
It's not unusual for wealthy travellers to bring their pets or even book a flight just for their beloved pet dog, cat or bird.
Cork said pets fly on about 20 per cent of St Albans-based PrivateFly's flights and can go in the passenger cabin.
She said: "We have had some more unusual animal flights, such as flying a much-loved family dog alone from London to Madrid to be reunited with her owner.
"We have also flown a parrot from Manchester to London, when the flight was out of its flight range."
Surbiton-based Air Charter Service, which has offices around the world, said a woman once booked a jet for her and her nine cats when she moved, while another customer booked one for their three cats, which stayed in their crates on the flight between Kansas and New York.
In other cases, passengers want to fly with some of the comforts of home or their favourite food or drink.
One traveller is such a big fan of the soft drink Fresca that he wanted it on his flight, even though it is not sold in Europe, said Cork.
That left the PrivateFly team with less than 24 hours to find it.
Cork said: "When he requested some for a flight out of London the following day, we quickly enlisted the help of a friendly airline pilot to airlift a crate of the desired beverage from New York to Heathrow.
"From there we put it in a taxi to London City Airport, just in time for takeoff."
She added: "Another health-conscious passenger wasn't sure where he wanted to fly, but it had to be home to the highest percentage grade organic coconuts.
"We sourced a farm in Fiji and arranged the flights."
While many customers have a reputation for eating caviar and lobster, a pizza delivery to the aircraft is more common than people think, said Cork.
For a number of couples, private jets have served as the setting for a romantic wedding proposal.
Air Charter Service recently helped one man pop the question on the anniversary of when he met his partner - and he brought both sets of parents along for the ride.
Richard Thompson, the private jet charter service's president of the Americas, said the flight out of Farmingdale, on Long Island in New York, took place just before midnight.
The private terminal was decorated with flowers and gifts, and a photographer was on board to capture the special moment.
Thompson said: "When they were airborne he proposed at the stroke of midnight - the anniversary of when they first met - and she said yes."
The couple - and their parents - celebrated with Champagne and desserts as they flew around the New York area and enjoyed the views.
The company often receives requests for flight attendants who speak a specific language, including French and Japanese.
One guest requested a female flight attendant who speaks Spanish and had a background in dancing.
Air Charter Service has also seen an increase in requests for flight attendants to wear uniforms.
George Galanopoulos, managing director of London Executive Aviation, said a stag group once asked for a Wilson volleyball with a red hand print on it - like Wilson the volleyball in the film Cast Away - and a stuffed monkey.
He said: "LEA's concierge service is available 24/7, 365 days a year. The team handles all types of requests for on-board requirements such as special food and drink choices to spa treatments and hairdressers as well as on the ground logistics such as parking and hotel options.
"The more bizarre requests are usually for items which we need to source for those travelling for a special event."
- Daily Mail