Yes, I suppose I should have thought of this before. Of course such a travel agency is going to exist. One that specializes in the overseas travels of missionaries, bringing the word of God to the heathen. They offer missionary flights, of course and the other sections of the site are interesting. They make the obvious point that given that all of their staff are commited Christians you know that they'll be honest. They have special contracts with the airlines for missionaries and as may of their people have done this work before then they'll know what you're going through and what your needs are.
You can also check out their section of testimonials, to see wat earlier users of the service have to say about it.
Well worth checking out.