The spelling of "am on trail" is straightforward once you understand the pronunciation. In IPA phonetic transcription, it is /æm ɒn treɪl/. The "am" sound is represented by the symbol /æ/, as in "cat" or "hat." "On" is pronounced with a short "o" sound, /ɒ/, as in "hot" or "not." Finally, "trail" is pronounced with a long "a" sound, /eɪ/, as in "ale" or "hay." Therefore, the correct spelling of this phrase is "am on trail."