My progress round the world isn't fast – it's stately, slightly creaky, preceded by a bosom fit for a galleon. I could sit in a corner, wring my hands and weep into a lettuce leaf and obsess about calorie-counting or I could do my best to ignore the disadvantages of being fat, 50s and arthritic and go round the world.

It's much more entertaining, if less carbon neutral. Except that if Air France-KLM have their way I might be grounded by simple economics. If I am forced to pay for two seats because some stick insect behind a desk decides that I am too broad, that's it – can't go.

Truthfully, planes aren't a lot of fun if you are overweight. It's cramped, uncomfortable and you just know that everyone is dreading sitting next to you, however nicely you smile. I always try and get the aisle seat because it's more comfortable both for me and anyone sitting next to me if I can overhang into the aisle, not into their space.

There is the muttered embarrassment of having to ask for a seat belt extension and wondering if the tray table in front of you will go down or will have to be manoeuvred round the tum. It's totally fatal if the person in front reclines their seatback because that uses up the last square inch of space you may have had available. There's the difficulty of using the controls for the light or screen because you can't wriggle to get at them. And then, of course, there are the endless miles of walking...

Of course, there will be the odd person who is so huge they do need two seats as a safety issue, but realistically, they are very few and far between. This is about money-grabbing economics.

This afternoon, I was looking up KLM flights to Dar es Salaam for my next trip. Good connections, great price, but if I have to get out my tape measure first, someone else gets my money.

Now if someone wants to start a fat-friendly airline, with comfortable seats, plenty of leg room and a welcome smile, I wonder how many others would flock to fly?

Freelance travel writer Melissa Shales blogs at www.worldatlarge.co.uk