Spanish term (edited): Por el Frente: Con aires delanteros No. 2

It's difficult to get to grips with this, but here is what I think it means.

This is part of a description of the property, specifying what it adjoins on each side. "Por el Frente" means at the front or in front of the property in question. "Con" means "linda con": the property borders/adjoins "aires delanteros No 2" at the front.

I think that part is fairly clear, but now comes the tricky part. A key term here is "aires". I believe this means airspace: in other words, the space above a property. Generally if you own a property you own the airspace above it too. So you can build on top of the existing roof of your property (if planning regulations allow you to). Or you can sell or let that space to someone else for them to use. In a condominium, the airspace above the building (from the roof upwards) is generally communal property.

Here's some supporting evidence for this meaning of "aires" in Peru:

"Una vivienda inscrita en Registros Públicos, te permite aumentar el valor económico de la propiedad: convierte en valor comercial los aires (techos)."
http://www.munlima.gob.pe/images/descargas/gerencias/GDU/SAL...

"AIRES COMUNES
Constituyen una copropiedad dentro de una edificación con secciones de propiedades exclusivas y se refiere aquella proyección que existe sobre el límite físico más elevado de la edificación, vale decir sobre el techo o la azotea si existiera, siempre sobre la superficie en que acabe el inmueble, por tanto no es posible confundirla con la azotea que si es parte física del inmueble y susceptible de ser señalada en la declaratoria de fábrica, mientras que los aires no son ambientes a declarar por cuanto aun no existen sino como proyección pero si pueden ser independizadas pudiendo tener su propia partida registral como inmueble independizado"
http://www.cofopri.gob.pe/media/2428/glosario-de-términos-co...

This page has a detailed explanation of the law on "aires":

" a) Definición de “aires”
Tradicionalmente, el término “aires” de una edificación ha sido definido como el techo del último piso de una edificación sujeta al régimen de propiedad exclusiva y propiedad común, techo que puede tener la calidad de zona común o de sección de propiedad exclusiva, supuesto último que deberá constar expresamente en el reglamento interno."
http://blog.pucp.edu.pe/blog/registralynotarial/2010/07/12/r...

So I believe we're talking about air rights here:

"Air rights are the property interest in the "space" above the earth's surface. Generally speaking, owning, or renting, land or a building includes the right to use and develop the space above the land without interference by others. [...]
The exact altitude(s) at which the airspace over private land becomes "public" airspace, or where the upward bounds of national sovereignty extends is often debated"
https://en.wikipedia.org/wiki/Air_rights

At this point it gets more obscure, but I presume that "aires delanteros" must mean "front airspace", and I think "no. 2" denotes a numbered section of airspace above land belonging to the condominium and in front of the property being described. When "aires delanteros" are followed by numbers in these descriptions, it always seems to be no. 1 or no. 2. In other words, I don't think "No. 2" refers to the number another property but to the number of the airspace.

See the following contract for a condominium, which has various references to "los aires delanteros nro. 1" and "los aires delanteros nro. 2", which are distinct from (for example) "los aires de la Calle El Rosario" (which is the airspace above the street):
https://elrosario207.files.wordpress.com/2007/04/independiza...

In other documents of this kind I have seen both "aires delanteros nº 1" and "aires de terceros".

So I think all you can do is call it "front airspace no. 2".