Manner vs. manor
A manner is (1) a way of doing something, (2) a bearing or demeanor, and (3) a type. The plural form, manners, refers to a manner of behavior considered to be social correct.
Constructions involving manner can often be shortened to single adverbs. For example, in a calm manner and in a public manner can give way to calmly and publicly. Some such phrases lack one-word equivalents, however—e.g., in a timely manner.
A manor is (1) the estate of a European lord, or (2) the main house of a large country estate.
Aid vs. aide
An aide is an assistant or helper. The word always refers to a person. Aid is a noun referring to (1) assistance, or (2) something that assists (e.g., a hearing aid or a visual aid), and it’s also a verb meaning to assist. Some dictionaries list aid as a variant of aide, but the words are generally kept separate in edited writing.
Both words derive from closely related French sources, but they entered English at different times. Aid came to English in the 15th century (and had several spellings in early use) and has borne a variety of meanings over the centuries.1 Aide entered English several centuries later, possibly as a shortened form of aide-de-camp, which refers to a military officer who assists a superior.