Literal envelopes that will fit the 11" Air?

[goodtimes5]

All these sleeves that look like manilla mailing envelopes to hold the 11" Air are too expensive for me. Are there any actual and literal manilla envelopes that can hold the 11" Air? I recently bought one, but the Air is a centimeter too long, and the envelope flap can't fold shut.

 

[foiden]

The Manilla Envelope that holds the 13" was likely the legal-sized envelope. However, for the 11", it may seem a bit too roomy.