private bool apendable(Flight f2)
{
if (this.parent == null || (this.end().CompareTo(f2.end()) < 0 && this.to == f2.from)) return true;
return false;
}
private bool apendable(Flight f2)
{
if (this.parent == null || (this.end().CompareTo(f2.end()) < 0 && this.to == f2.from)) return true;
return false;
}