If they have been poorly bled, and there is air in the system then they can feel a bit spongy after air travel. (My experience with MTB levers).
You can isolate the reservoir - where the air is - from the caliper and hoses by elastic banding the leavers closed with some pad spacers in the calipers.
You can isolate the reservoir - where the air is - from the caliper and hoses by elastic banding the leavers closed with some pad spacers in the calipers.