Flow path assemblies and gas turbine engines are provided. A flow path assembly may comprise a combustor dome positioned at a forward end of a combustor of a combustion section of a gas turbine engine, and a unitary outer wall including a combustor portion extending through the combustion section and a turbine portion extending through at least a first turbine stage of a turbine section of the gas turbine engine. The combustor portion and the turbine portion are integrally formed as a single unitary structure. The flow path assembly also comprises an inner wall extending from the forward end of the combustor through at least the combustion section. The combustor dome extends radially from the unitary outer wall to the inner wall and is configured to move axially with respect to the inner wall and the unitary outer wall. Other flow path assemblies and gas turbine engine configurations are provided.