How much can this fit in it?

Would it fit onto a pikkolo? I have looked at it online and I think it might but am not sure.

Would it also fit onto a maclaran stroller, I know I would have to be careful not to weigh it down and cause tipping but would be good to go out for the day and take the pikkolo and stroller when we go away to canada in April.

Iam also interested in this for fitting on the carrier at airports/inflight. As it is smaller I would be able to have the basics in it - few nappies, food and have extras in a larger bag overhead.