The protest is against a retention of a meteorological mast in Bracklyn.
Ryanair boss Michael O'Leary is among those objecting to plans for a new windfarm in Westmeath.
His horse racing stud, Gigginstown House, has filed an appeal with An Bord Pleanála over Westmeath County Council's decision to grant permission to retain a meteorological mast in Bracklyn and extend its height from 80 to 100 metres.
It's associated with a project to develop nine of what would be the tallest wind turbines in Ireland at the site.
Delvin WInd Information Committee are also appealing the decision.
The case is due to be decided on 23rd March.