Is it true you can get dirt cheap international flights if you turn upto an airport & just get a spare seat?

No. I lived near Gatwick, and a few times enquired at the check-in desks for cheap seats for immediate departure, and the prices were higher than if I had booked a few days in advance.

It is called "stand-by" and that is what it is. You may stand there for a long time. You might make it to one city and have to stand there again for your next flight. Too much trouble

I have heard that some bargains can be had but I think it;s risky and unlikely. You would be far better going to a travel agent and seeing what last minute holidays and flights are available.

They are called Sandby fares. It depends on the airline, how good you are at negotiating and remember you have to come home again and your language skills may not be good enough to bargain in a foreign airport. .

It's true. I turned up at Gatwick and got a dirt cheap flight to Novosibirsk with Trans-Ural Airlines. My wife got a dirtier and cheaper flight to Ouagadougou with Burkina Faso International Airways. We had a lovely couple of weeks apart.

Generally no, you can not turn up and expect cheap seats. Airlines have figured out that doing this conditions customers to expect cheap flights, so instead they use "yield management" to make the most profit from each flight, and filling last minute seats cheaply does not support this model. That said, with the right tools, you might be able to do alright with a "normal" advance purchase fare--with as few as 3 days advance. It depends where you'll be travelling from, and where you want to go.

i was wondering this myself, ill try and find out and get back to ya

I wouldn't chance it if you want to be flying together. They may have a spare seat, but rarely two at a time. If you are willing to fly separately and arrive in your goal city at different times (even different days) it's worth a try.