Yes, some use them some do not. airlinesapps.com uses letters of recommendations in a digital format. The person gets an email, they then log in and answer the questions and enter their LOR. Some online apps give you the option to upload PDF or Word files. Print out your letter, have them sign it, scan it to PDF, upload.
In any case, get a LORs from your bosses. If you are going to apply to lots of airlines, have a general LOR or ask them for permission to substitute companies on the letter.