A fully-collapsible portable stroller without covers and baskets is possible to carry on only if the size is less than width 100 cm x depth 20 cm x height 20cm. (One stroller free of charge for one child, if the size meets its requirement)
When you check in the stroller, you can pick up at the destination baggage claim area.
Or you can use it to the departure gate and leave it to the staff.
Then it will be loaded in the baggage compartment and you can pick up in front of the arrival gate (some airports excluded)