The client, the site, the job and the check that goes with it.
Most operators keep clients in one place, jobs in another and the airspace check nowhere at all. Here the job is the record, and everything hangs off it.
What it holds
One client, as many sites as they have. Every job, check and invoice for that site stays with it, so the fourth visit starts where the third finished.
Who to call on the day, who signs off the work and who pays the invoice, kept against the client rather than in your phone.
Date, site, scope and status. Assign the pilot and the aircraft from your operator record, so the qualification and the class marking come with them.
Price the work, send it, and when it is accepted the job is already built. The quote becomes the invoice in one step.
Attach the airspace check and the standard operating procedure to the job. When a client or an insurer asks what you did, the answer is one record, not a search through your email.