Start with the p generation with the following genotypes (aa x aa). based on classical mendelian inheritance, how will a cross between two homozygous parents, one dominant and one recessive, influence future generations?

The genotype of the generation resulting from the given P ( parental generation) is Aa that is all offsprings in the first generation will be heterozygous dominant.  

The genotype of the parents is AA and aa and the gametes produced by these parents are A and a respectively.

When these gametes fuse, they result in the offsprings with genotype Aa. This represents a dominant phenotype due to the presence of dominant gene  (  a gene that masks the expression of recessive gene and expresses itself), which is A in this case.

youre right there are