Air flow air mouth at the back of portable pizza oven

[paddywide]

Hi, to the portable stainless steel pizza oven, generally they are really compact, probably the floor is only 34 to 40cm width. There are wood and gas version. To the wood/pallet version of pizza oven, I notice there is a hold at the end of the oven, I guess it's to supply the air for burning.
Why doesn't the traditional brick/clay oven (1m diameter) have an extra hole at the back of the oven?
What are the differences between them? be the mean of heat-up speed, the temperature, fuel-saving, air-flow and etc.
Does the gas version portable oven need a hole as well?

[Petter]

With this type of oven (narrow and deep), you don't get the same air circulation as in a large round ditto. The oxygen sucked though the opening is not enough to fuel the combustion. I've tried without the rear vented but ended up with a hole in the back with an adjustable size of ~ 2.5 x 12 cm. It also burns the coals very efficient and enabled the use of a low heat shield between the fire and pizza for a closer placement and a more even bake.