@DataGuru
Both Fillout and Jotform keep their own internal databases of your form submissions, so if your form is functioning, you will never lose your data — even if Airtable is down.
I’m not 100% sure how JotForm handles it, but Fillout will send you an email notification to let you know that a form was submitted but it didn’t make its way into Airtable.
With either Fillout or JotForm, you could always use Make to automatically push through your failed form submissions to Airtable as soon as Airtable is back up again. (Otherwise, I think you need to manually input the failed form submissions.)
And even if Airtable has no downtime at all, you will still have 100% of your form submissions on file with JotForm or Fillout.