Rayearth

Both are condensed and dark, twisted retellings of their cute, fun, and fantastical shoujo anime counterparts about schoolgirls being transported to another magical world that they have been chosen to save. Not to mention both are about magical girls and mechs that are actually living beings- In both cases, the mechs are actually dragons (or a bird and a lion, in the case of the 2 other mechs in Rayearth). The only notable difference is that where Escaflowne has a male and female hero, Rayearth has 3 heroines.  

They’re both alternative versions of the same series They’re both popular Shojo series They’re both dubbed in New York by a New York cast 

The Rayearth OVA is basically just a PG-13 recitation of Iczer-1, so you obviously don't get the steamy Yuri vibes and tentacle rape abound that you do with Iczer. Both were directed by the madcap Hirano Toshiki and both present a very similar narrative outline: Earth gets invaded by extrinsic forces leaving the target cities completely ravaged, causing a random, callow schoolgirl (or girls, in the case of Rayearth) to be inexplicably chosen, by an unearthly being(s), as the predestined savior(s) of the planet. Oh, and then they all get into giant fuckin' robots and thwack the shit out of each other. The end. 

From an era were CUDDLY girls were innocent but are tough as nails, AND THATS WHY they are worty in these anime as the main persona! with all the sugarcoating and all :) 

Rayearth is quite literally just Magic Knight Rayearth put into the world of X/1999. CLAMP loves their crossovers and if you take a good look you will notice that the unifrms the Rayearth girls wear in this OVA are identical to the later school uniforms in X/1999. The setting is also a dark Tokyo being torn asunder, much like X.