Buenos Aires non-standard postmarks part 2

I do not know the meaning of the letters appended to Buenos Aires in these postmarks. The V.A. that is added to E.R.V. to come up with E.R.V.V.A. 2 could mean VIA AEREA.

E.R.V. 1o and 2o :: E









VIA AEREA :: E



E.R.V.V.A.2 :: E