Your father's error is that he doesn't know aviaiton, and he doesn't know the costs beyond the capital acquisition price.
Take the $25k price as the example point. Assume sales tax, if applicable (it is in most states) runs ~5%, or $1250. Estimate that insurance for a solo student pilot/owner will run ~$1750, give or take (call a broker for a quote). Hanger of a year runs ~$1900/year ($160/mo) around here (check local market for an accurate estimate--it could be a whole bunch more). The average student takes ~55 hours to the private pilot certificate. Assume a C172 averages 8 gph, 55 hours, $3.50/gal, so fuel is ~$1550. Sum all of the above, you have $6450 invested in the first year and 55 hours of training, or $117/hour, and we haven't allowed for the first annual, normal wear & tear, nor banked any funds away for the inevitable surprise. Nor does our per hour estimate include costs beyond sales tax of finding and purchasing the aircraft--costs that usual run into several thousand dollars.
~$117+/hour minimum cost for a beater C172 that you could probably rent for ~$70, wet, without any additional financial risk or investment. That's what your father doesn't realize.
