Originally Posted by MSPeconomist

Yes, don't even try this.

I'd suggest that you ask the charity if it has access to any special flight deals, such as contract, group, or bulk fares, that you could use. Unfortunately these are unlikely to earn any FF benefits and might not give date or routing choices. Your plane tickets might be tax deductible as a charitable contribution or could even be tax deductible if donated by your parent but IANAL.