A Royal Naval Air Service without an independent RAF

Could the Royal Navy have retained its own air arm if the First World War ended earlier?

Yes; Britain might have followed the American and Japanese pattern of separate army and naval aviation, especially for shipboard flying, rather than creating a single independent air force.

Retaining a distinct naval aviation service would be easier to justify if the war ended before the later institutional settlement. Britain could then follow the American and Japanese pattern of separate army and naval air organisations rather than concentrating all aircraft in an independent service. A Royal Naval Air Service could focus on shipboard flying while an army air arm handled land-based missions. Mobile sea bases impose different logistical, operational, strategic, and force-development demands from permanent airfields ashore.