The question of whether “aeroplane” has a long or short vowel depends on how one pronounces the word. In general, the pronunciation of “aeroplane” can vary between different English dialects and accents.
If we consider the traditional British English pronunciation, the vowel sound in “aeroplane” is typically a long vowel. The pronunciation is closer to “air-uh-plane” or “air-oh-plane,” with the first syllable sounding like the word “air” (as in the air we breathe) and the second syllable having a schwa sound (uh) or an “oh” sound.
In this pronunciation, the vowel sound in the first syllable is a diphthong, which means it is a combination of two vowel sounds. The “ai” in “air” represents the long vowel sound /ɛə/ (similar to the vowel sound in words like “air” or “care”), followed by the schwa sound /ə/. So, the pronunciation of “aeroplane” in British English can be roughly transcribed as /ɛərəpleɪn/.
However, in some accents of English, such as certain American English dialects, the pronunciation of “aeroplane” may have a short vowel sound. In these accents, the word may be pronounced more like “air-uh-plan” or “air-uh-plain,” with the vowel sound in the first syllable being a short “a” sound, similar to the vowel sound in words like “cat” or “hat.” The vowel sound in the second syllable would still be a schwa sound.
So, to summarize, the pronunciation of “aeroplane” can have both long and short vowel sounds depending on the accent and dialect of English being spoken. The traditional British English pronunciation tends to have a long vowel sound in the first syllable, while some American English accents may have a short vowel sound.