'UNavMovementComponent::IsFlying': non-standard syntax; use '&' to create a pointer to member

void ACasey::CrouchStart()
{
FVector LaunchDir = CharacterCamera->GetForwardVector();
if ((IsSprinting == true) && (GetMovementComponent()->IsFalling == false))
{
IsSliding = true;
LaunchCharacter(LaunchDir*3000,true,false);
Crouch();
}
else
Crouch();
}

Your missing () in IsFalling()

void ACasey::CrouchStart()
 {
     FVector LaunchDir = CharacterCamera->GetForwardVector();
     if ((IsSprinting == true) && (GetMovementComponent()->IsFalling() == false))
     {
         IsSliding = true;
         LaunchCharacter(LaunchDir*3000,true,false);
         Crouch();
     }
     else
     Crouch();
 }

Thank you, I can’t believe I omitted such a simple detail.