Transporting Koi

Hi All

I am about to transport 4x 12" Koi approx 1-11/2 hours in a car.

I have plenty of bags and or containers for the job....but will I need
oxygen?
I could use Ice to cool the containers and slow metabolisms etc. as the temp
may get high (25c +)SE England (wishful thinking !!)

OR
Does anyone know of local supplier of cheap airpumps to run a stone etc from
cigar lighter ?

The longest journey I've ever attempted was with 6" koi for 30mins without
oxygen etc..

ANY and ALL advice welcome!!!

Many thanks