Definitely down, but I haven't seen it publicly quantified how the sharp reduction in cross-border vehicle traffic has affected enplanements at BLI. I recall a Port of Bellingham spokesperson saying generally that it wasn't as dramatic a drop as the vehicle traffic percentage.

Allegiant tries to generate and sop up as much of the British Columbia demand as it can (it flies to six destinations from BLI and the Port of Bellingham says historically, Allegiant has had 50-60% market share). AS is likely affected, too, but it's hard to say how much since Allegiant actively markets to the budget-minded Canadian leisure traveler.