Sluggish demand — two little words that can send big chills down Hawaii’s tourism spine.

This week brought a double dose of that, first from Delta Air Lines, then the next day from Hawaiian Airlines’ parent company.

“Year-over-year visitor growth from North America to Hawaii remains positive, but at a slower pace than industry capacity growth,” Hawaiian Holdings Inc. said Wednesday, in contracting its outlook for this quarter.

Hawaiian’s gloomier forecast came after Delta had pared back on its unit revenue outlook to a 3.5 percent increase, down from its previous prediction of up to 5 percent.

One factor that might take the edge off of Hawaiian Air’s news: it cited lower-than-expected demand between the neighbor islands, mainly to Hawaii island where lava eruptions apparently kept visitors away. This had been anticipated since the eruptions began, so let’s hope the temporary down-blip was due to this rare act of nature.

Still, this week’s downcasts from Delta then Hawaiian come on the heels of other air-lift news that cited sluggish demand. Scoot, the budget airline that brought flights to and from Singapore four times weekly via Osaka, Japan, has announced that it would be discontinuing service to Hawaii after May due to lagging demand.

After enjoying nearly seven years of record visitor numbers, Hawaii tourism will need to work that much harder to keep things soaring.