Solution elaboration

Suppose we have a plane with certain weight limit and a list of passenger weights. Say the plane's weight limit is 150 and at a time it can carry two passengers. We need to find the minimum number of flights the plane needs to make. My approach to this was similar to the one mentioned in the following link With the exception being that instead of checking if the arrival time is less than departure time, I am checking if the sum of the weights of two passengers is less than 150 or not, if it's correct we increment the no of flights. Please let me know if I was on the right track. I was only able to pass 2 /3 test cases. I am thinking my approach is wrong and it should be solved using dynamic programming like a knapsack.(Please let me know as this was an interview question).