Does Spain have proprietary rights to "Frittata"? I thought it was originally an egg-based Italian dish.
Further exposing my ignorance, I'll admit that arguments like Spanish versus Italian cuisines seem no more important to me than Tennessee Whiskey versus Kentucky Bourban.
I only flip a broiled frittata if I've screwed up and want to hide the top.
The older I get the more I recognize how often accusations of stupidity were mirror images.
Spanish Omelette does seem to be very similar to a Frittata. If I have plenty of eggs and a supply of suitable vegetables to use up, I won't split the difference! I never flip mine, just cook till the egg mix is still slightly underdone and then pop under a hot grill (broiler?) Sometimes, if the mood takes me, I grate cheese over the top too!