There is tons of KL/DL/AZ availability. Random KL itinerary in April:

Madrid (MAD) to Chicago (ORD) - Fri, Apr 12
Madrid (MAD) to Amsterdam (AMS) - Fri, Apr 12
KLM 1708 Dep: 6:00AM Arr: 8:35AM 2h 35m Boeing 737 Economy (L)
Layover in AMS 4h 5m

Amsterdam (AMS) to Chicago (ORD) - Fri, Apr 12
KLM 611 Dep: 12:40PM Arr: 2:10PM 8h 30m Boeing 747 Economy (R)



Chicago (ORD) to Madrid (MAD) - Sun, Apr 14
Chicago (ORD) to New York (JFK) - Sun, Apr 14
KLM 5623 Dep: 3:00PM Arr: 6:20PM 2h 20m Canadair Reg. Jet Economy (R)
OPERATED BY PINNACLE DBA DELTA CONNECTION Layover in JFK 1h 10m

New York (JFK) to Madrid (MAD) - Sun, Apr 14
KLM 6126 Dep: 7:30PM Arr: 9:15AM 7h 45m Boeing 767 Economy (R)
OPERATED BY DELTA Mon, Apr 15

Cost per passenger (including taxes & fees) $504.89
Total cost for 1 passenger $504.89