It would cause no harm, but you need to be sure it can deliver enough current (amps) to compensate for the usual parasitic loads in an Airstream.
These loads are stuff like the Propane Detector, and the Sub-woofer speaker, as two examples that come immediately to mind.
I use DelTran battery tenders for a lot of standby charging applications. Haven't had an issue yet, unless I forget to connect it to the battery...
Rich, KE4GNK/AE, Overkill Engineering Dept.
'The Silver HamShack' ('07 International 22FB CCD 75th Anniversary)
Multiple Yaesu Ham Radios inside and many antennae sprouting from roof, ProPride hitch, Prodigy P2 controller.
2012 shortbed CrewMax 4x4 Toyota Tacoma TV with more antennae on it.