@Gary805 the aitbnb extenuating circumstances clause for a full refund only extends till May 31st. If your booking is past this date, your host is right, you will have to wait and see if airbnb extends the window for cancelling for a full refund under a strict cancellation policy.
As your flights are cancelled, you may be eligible for a full refund anyway, but you would need to contact airbnb customer services and provide a proof of the flight cancellation.
If your booking is within the current policy, it may be a software bug or it may be the fact that airbnb is changing their policies yet again.
If everything fails, you may be able to claim from your travel insurance or reverse your credit card payment.