I have no experience of jars or pouches, my only suggestion is to take things you have tried before which you know LO likes.
Otherwise you could offer the odd bit of your own food or pick up some fresh fruit (bananas, strawberries, cucumber, capsicum etc) on your travels. I've often bought a capsicum and just ripped it open, tapped out the seeds and torn a bit off for DS to much on as finger food.
Bread sticks travel well.
Here we can get individual pots of fruit in fruit juice which just have a film seal which is, they are not a 'baby food' as such, just fruit, I packed a couple when I took DS away.