I recently travelled with the following small games and can recommend them.

Sprawlopolis - Lovely co-op city builder with 18 cards, much more replayable than you'd think.

Fugitive - A great cat and mouse/hidden movement game with numbered cards. Either flee as the fugitive or hunt as the marshal.

Air land and Sea - A tactical game with the added wrinkle of choosing when/if to withdraw.

Monopoly Deal - A classic, fast, fun, ruthless. Monopoly as it should be.

Hive Pocket - Chess like, strategic, tactile and can be played pretty much anywhere.

Stew - A simple bluffing card game of creating a stew together and working out when the best time is to eat the stew, if at all.

Hope this helps!