Class with predefined ellipsoids
I would explicitly refer the constants in class variables :

class Elipsoids:
    airy = Elipsoid(6377563.396, 299.3249646, 'airy', 'Airy 1830', 'Britain', 7001),
    mod_airy = Elipsoid(6377340.189, 299.3249646, 'mod_airy', 'Airy Modified 1849', 'Ireland', 7002),
    ...


This way :


You get rid of global variables : you simply do module.Elipsoids.airy .
You get rid of dirty assigning code
You can get rid of alias if it's not used anywhere else in the code
You get more readable access to variables