These are the same women as depicted in the related photo, Sumba Women in Traditional Dress - Waiting to Dance, now dancing.
What’s somewhat ironic here is that the ceremony is being held to welcome church dignitaries arriving at the airport - but this Sumbanese traditional dance is (or was) actually performed in days of yore to welcome back their men back from a fight or other type of less-than-peaceful activity.
The Sumbanese are heavily animistic, especially in the rural areas - and all throughout Sumba. The western portion of Sumba is even more heavily animistic than the more-travelled eastern region. In animism, everyday organic objects, eg, trees, rocks and plants, are invested with active spirits to which prayers are delivered.