aeronautical

The story

1. Proto-Indo-European*h₂ews-
2. Proto-Indo-European*h₂ewsér
3. Proto-Hellenic*auhḗr
4. Ancient Greekᾱ̓ήρ (āḗr)
5. Ancient Greekἀέρος (aéros)
6. Englishaero-
7. Proto-Indo-European*(s)neh₂-
8. Proto-Indo-European*néh₂us
9. Ancient Greekναῦς (naûs)
10. Ancient Greekναύτης (naútēs)
11. Ancient Greekναυτικός (nautikós)
12. Classical Latinnauticus
13. Middle Frenchnautique
14. Classical Latinnauticus
15. Proto-Indo-European*h₂el-
16. Proto-Indo-European*h₂élisder.?
17. Englishnautical
18. English todayaeronautical

From aero- + nautical.