It would be too early to send him the notice for the recovery of the airfare and other charges. First, understand why he has been absenting? Has he met with an accident? Does his family member has some problem? Is there marital discord or something like that? Occasionally, an employee behaves immaturely.
So as a first step, send the Security Officer (SO) to his home and find out why he is absenting from his duties. SO must act professionally and find out the exact reasons for absence. SO should not get any angry but by chance, there is a physical assault, he should handle it professionally.
Make a separate file for this case and this report should be filed in the filed. Your letter to SO should be the first enclosure of the file. On completion of the visit, the SO should send the official report. Make all the correspondence through hard copies only. There is no need to send an email.
If the correct reasons are ascertained then well and good. If not then send the notice for absence from the duties without authorisation. In this notice, do not mention anything related to the recovery. Please wait for your reply. If the reply is not received then order the domestic enquiry and tell him to depose before the enquiry. The Enquiry Officer (EO) should investigate not just the unauthorised absence but losses caused to the company owing to the absence also.
As of now, you may follow the above-mentioned steps. Further guidance will be given as things unfold.
From India, Bangalore
From India, New Delhi