Business class is beyond the budget of most travellers... so how can you improve your chances of a free upgrade?
Successful blagging comes down to status, timing and charm... in that order.
Sadly, there's no silver bullet or foolproof formula (if there was, I would be sipping champagne in business class, and not writing tips about blagging upgrades).
The only guaranteed way to get an upgrade is to pay for one... in cash or points. There are ways to boost your chances of turning left for free, however.
Free upgrades are the holy grail of travel hacks, and they generally happen when economy is over-booked (as opposed to business class seats being empty).
When they do, upgrades tend to be either automatically allocated or given to customers with high points in the airline's frequent-flyer scheme.
It seems counter-intuitive, but travelling on busy routes therefore increases your chances - particularly if there are likely to be a lot of families or groups on board.
Aer Lingus flights to Orlando might be a good example here. Off-peak (e.g. bank holiday) flight times to destinations like New York, Boston and Chicago could also reap rewards. Monday morning flights to Brussels – not so much.
Airlines handle upgrades differently, but as a rule of thumb it pays to a) join a loyalty programme and b) accumulate as many air miles as possible.
The more points you have, the more desirable your status within the programme, with regular customers generally given priority when upgrades are available.
"The only advice we would offer is making sure to collect and use your Skywards Miles to upgrade tickets to Business or First Class," an Emirates spokesperson told us.
“It is sometimes necessary to upgrade customers,” BA told Telegraph Travel. “This is rare and will normally apply to frequent flyers who are members of our loyalty programme first.”
“Passengers who paid more for their tickets are more likely to be upgraded than passengers who bought a discounted ticket," added a spokesman for Lufthansa.
You don't have to look like Don Draper, but dressing well definitely helps when it comes to upgrades – although if your request fails, it's no fun flying economy in a three-piece suit.
Don't even try requesting an upgrade when tipsy or drunk, and unless you're a gazillionaire, football shirts, flip-flops, tank-tops and hygiene failures are also no-no's.
If a single seat becomes available up front, solo travellers are more likely to benefit than couples or groups, so lonely souls are at a definite advantage there.
You've nothing to lose by asking.
As any student of human behaviour knows, however, there are different ways to ask a question. With airlines, the trick is to make a polite request at check-in (rather than the gate).
Airport staff deal with a lot of frustrated and demanding passengers, so a pleasant approach is much more likely to win favours. Arrive early to maximise your chances, and mentioning a honeymoon, birthday or anniversary won't harm your case, either.
Virgin Atlantic once revealed the least convincing excuses offered by customers in an attempt to get bumped up the cabin. Our favourites?
What about actually paying for an upgrade?
They don't have to cost the earth. Aer Lingus has an 'Upgrade Yourself' feature that invites passengers to bid on an upgrade, for example (on a sliding scale of €350 to €950, based on a flight recently took to Chicago), with top bidders awarded any available seats.
Emirates and Aer Lingus run regular business class sales, too.