Methods for forming airfoils, core assemblies, and airfoils for gas turbine engines are described. The methods include forming an airfoil body about a core assembly configured to define one or more internal cavities of the airfoil body, the core assembly comprising at least core structure having a purge slot protrusion extending from a portion of the core structure, removing the core assembly from the airfoil body to form one or more internal cavities, wherein at least one internal cavity has a cavity extension define by the purge slot protrusion, and forming a squealer pocket in a tip of the formed airfoil body, wherein a cavity purge slot is formed at the cavity extension to fluidly connect the respect internal cavity with the squealer pocket.