Ader or Aider: How To spell?

The word Ader is misspelled against Aider, a noun meaning "One who, or that which, aids."

Word begins with consecutive vowels 'AI' followed by alphabets 'der' is misspelled as 'A'
Wrong Spelling:  a-der 
Correct Spelling:  ai-der 
Explore spell check of Aider to spell without errors.

You might be interested to know

Eguillette or Aiguillette?

Imer or Aimer?

Orless or Airless?