The /eə/ sound is spelled with <air> or <aer>.
As /eə/ is fairly rare, only occurring in 962 words in the dictionary, this was a fairly easy list to work out manually. Most of the words arise from compounds beginning air-. Two pairs arise from deleting a suffix -aire. There are very few others since the /eə/ vowel is usually the nucleus of a stressed syllable. I am not quite sure of the status of sierra/sirrah, particularly since sirrah is rather archaic.
The density value is 5.5%. The set makes 31 sematic distinctions, giving a loading of 58%.
aerate rate aerated rated aerating rating aerates rates airbed bed airbeds beds airborne born aircraft craft aircrew crew airfield field airfields fields airflow flow airframe frame airframes frames airing ring airings rings airline line airlines lines airliner liner airliners liners airmail mail airmail male airport port airports ports airraid raid airraids raids airship ship airships ships airstrip strip airstrips strips airtight tight airway way airways ways airway weigh airways weighs airwoman woman airwomen women airworthy worthy bearing bring bearings brings concessionaire concession concessionaires concessions corsair course heirloom loom heirlooms looms impair imp impairs imps Kildare killed questionnaire question questionnaires questions sierra sirrah sierras sirrahs staring string
John Higgins, Shaftesbury, December 2010.