Ready?
The Arabic "h" in Etihad is a voiceless pharyngeal fricative. That means that the sides in the vocal apparatus (throat) approximate one another (but do not touch) and the vocal cords are not vibrating to make a sound. The original Hebrew "ע" (which is still retained by many Sephardim) is a voiced pharyngeal fricative. It is made in the same location in the throat and in the same manner as the Arabic "h", except that the vocal cords are vibrating so a sound is emitted. If you rest your fingers on your Adam's apple you can feel the difference between a "k" (voiceless) and a "g" (voiced). The same difference between the Arabic "h" and the Hebrew "ע".
The English "h" is a voiceless glottal fricative. The approximating parts of the vocal apparatus is further down, between the vocal cords.
The original Hebrew "ח" was a voiceless pharyngeal fricative like the Arabic "h" and the Yemenites still use it, but most Sephardic dialects have been influenced by the hosting country's language and the vocal apparatus constrictions have moved more forward to the uvular location or even more forward than that to the velar location (like today's modern Israeli Hebrew "ח").
To summaraize:
Velar--Uvular--Pharyngeal--Glottal = Modern Hebrew "ח"--Sephardic Hebrew "ח"--Yemenite "ח" (and Arabic "h")--English "h"
The Arabic "h" in 'Etihad' is closer to the English "h" than the Mםdern Hebrew "ח", but since Modern Hebrew does not use an "h" sound for its "ה" anymore, the closest sound in Hebrew to the Arabic "h" would, indeed, be the "ח".
Bottom Line: English and Hebrew speakers are both spelling and pronouncing Etihad's name the best they can for their language.
