Jettison sits next to 4 phonetic neighbors — Jett, Jackson, and Garrison are the closest matches by sound. Most share Jettison's Old French via Latin-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"to throw overboard, to cast away"
"chance, fate, the throw"
"dearly loved"
"surname transferred to given name"
"one who farms the land"
"hawk-like; stately"
"divinely favored"
"undulating; like a wave"
"The lord is high"
"initials: various combinations (Andrew Charles, Anthony Cole, etc.)"
"weapon, mace bearer"
Similar sound: These names share phonetic patterns with Jettison — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Old French via Latin origins, giving them the same cultural heritage as Jettison.
Rhythm: Jettison is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.