The same spelling difference applies to the adjective favourable or favorable and the noun or adjective favourite or favorite. In British English, “favourable” and “favourite” are correct. In American English, “favorable” and “favorite” are correct.

In UK English, “favourite” and “favourable” (with a “u”) are standard. In US English, “favorite” and “favorable” (with no “u”) are correct.

In UK English, “favourite” (with a “u”) is standard. In US English, “favorite” (no “u”) is the correct spelling.

"Favorable" is used in American English, where the spelling conventions tend to omit the "u" found in certain words. On the other hand, "Favourable" is the preferred spelling in British English, retaining the "u" that is characteristic of many words shared between British and American English but spelled differently due to regional preferences.