How to travel with Avent bottle & Evenflo nipple?

I use the glass Philips Avent bottles with Evenflo balance+ wide neck nipples. this works perfect at home but the Avent bottle cap doesn’t fit with the Evenflo nipples—it squishes the nipple down. Has anyone found a cover on Amazon or something that fits? If not, how do you travel with the bottles? I don’t want to mess up the nipples; they’re so hard to find!