The word aerialists is playable in Words With Friends™, no blanks required. Because it is longer than 7 letters, you would have to play off an existing word or do it in several moves.
Words With Friends™ Letter Score: 11
Highest Scoring Words With Friends™ Play In The Letters aerialists
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Seven Letter Word Alert: (24 words)
aerials, airiest, airless, aliases, artless, atlases, atresia, irisate, lariats, liaises, realist, relists, resails, retails, sailers, saltier, satires, searats, seastar, serials, siltier, slaters, slatier, tarsals