Sometimes, sellers will provide you with AC power cords that are just too short for your needs. And, if that is what you need access to, you can be in quite a pickle. Well, this is just another reason why it is a good idea to pack some extensions cords with you on your trips.
Electric air pumps will be fine to be powered with an extension cord as they do not suck a great deal of power when they are in operation. But, to avoid voltage drops, you can consider using the shortest cord that you possibly can.