You can use this versatile stopper with an airlock or without. Either insert an airlock into the center hole, or create a solid stopper by adding a plug.

This #5 Stopper With Hole can be used in any bottle, carboy, or jug with a 15/16" - 1 1/16" opening. It can be used with an airlock or without, by simply using a #000 solid stopper (FE400) to plug/unplug the hole. Easy to clean and sanitize. Size 15/16" - 1 1/16".