The most common and most likely answer to this crossword clue is the 8 letter word TITANIUM
T
I
T
A
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M
More clues leading to the result TITANIUM
- Note thanks miners for guarding one metallic element
- Oberon’s queen almost starts to understand Mustard-seed’s element
- Mongrel, a mutt in one’s element
- Jumbo taken by author’s boarded by posh element
- Volatile bituminate shedding casing to reveal element useful for aeronautics
- It symbolises a metal when spinning
- Tin contracted, then expanded as metal
- Element of hesitation after Queen docked
- Mutant 2 transmuted metal
- Metallic element: I hide one in stomach
Buddy explains!

The straight part
We know that "element useful for aeronautics" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case element useful for aeronautics = titanium.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does TITANIUM mean?
TITANIUM noun- A chemical element, atomic number 22; it is a strong, corrosion-resistant transition metal, used to make light alloys for aircraft etc.
- A single atom of this element.