Both compounds have dispersion forces present between their molecules. All substances exhibit dispersion forces. A common misconception is that they are only present in non-polar substances. As long as there are electrons present, dispersion forces are present between the molecules. Propanal's molar mass of 58 compared to Ethylamine's molar mass of 45 suggests that dispersion forces are more important in propanal due to the increased polarizability of the electron cloud.
In the case of ethylamine, since there is an N-H on one end of the structure there could be hydrogen bonding occurring between ethylamine molecules at that location. Remember, hydrogen bonding is FON (whenever you see hydrogen bound to Fluorine, Oxygen, or Nitrogen, hydrogen bonding can potentially occur between those molecules at those locations).
In propanal we would say that dipole-dipole forces are present due to the C=O at one end of the molecule. The C=O double bond would certainly be polar due to the electronegativity differences between carbon and oxygen, but we wouldn't characterize interactions propanal molecules have with each other as being hydrogen bonding.
