The term SEASIDE FLIER can be broken down into two crossword solutions: ERN (3 letters) and ERNE (4 letters). ERN is a type of bird, also known as a cormorant, which is found near bodies of water such as lakes, rivers, and seas. ERNE is a type of bird, also known as a sea eagle, which is found near coastal areas and is known for its ability to soar high in the sky. Both birds are known for their impressive flying abilities, making them ideal candidates for the term SEASIDE FLIER.